{"appState":{"pageLoadApiCallsStatus":true},"articleState":{"article":{"headers":{"creationTime":"2017-11-29T04:57:55+00:00","modifiedTime":"2017-11-29T04:57:55+00:00","timestamp":"2022-09-14T18:16:03+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"https://dummies-api.dummies.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Study Skills & Test Prep","_links":{"self":"https://dummies-api.dummies.com/v2/categories/33772"},"slug":"study-skills-test-prep","categoryId":33772},{"name":"GED","_links":{"self":"https://dummies-api.dummies.com/v2/categories/33783"},"slug":"ged","categoryId":33783}],"title":"GED Math Extra Prep: Proportions","strippedTitle":"ged math extra prep: proportions","slug":"ged-math-extra-prep-proportions","canonicalUrl":"","seo":{"metaDescription":"One or two questions on the GED Math test will ask you to find an unknown quantity of something, using a proportional relationship. The following practice quest","noIndex":0,"noFollow":0},"content":"One or two questions on the GED Math test will ask you to find an unknown quantity of something, using a proportional relationship. The following practice questions ask you to do this by setting up a proportion where you are given three related values and you have to find the missing fourth value.\r\n<h2 id=\"tab1\" >Practice Questions</h2>\r\n<ol>\r\n \t<li>On a sunny day, a tree casts a shadow that is 33 feet long. At the same time, a nearby 4-foot-tall mailbox casts a shadow that is 5.5 feet long. What is the height of the tree? Round your answer to the nearest foot.\r\n\r\n<strong>A.</strong> 24 feet\r\n<strong>B.</strong> 33 feet\r\n<strong>C.</strong> 38 feet\r\n<strong>D.</strong> 45 feet</li>\r\n \t<li>Meg can swim 4 laps in 11 minutes. How long should she plan to practice if she needs to swim 10 laps, assuming her speed is constant?\r\n\r\n<strong>A.</strong> 4.4\r\n<strong>B.</strong> 15.7\r\n<strong>C.</strong> 22\r\n<strong>D.</strong> 27.5</li>\r\n</ol>\r\n<h2 id=\"tab2\" >Answers and Explanations</h2>\r\n<ol>\r\n \t<li>The correct answer is A.\r\n\r\nSet up a proportion for the mailbox with the height as the numerator of the fraction and the shadow length as the denominator:\r\n\r\n<img class=\"alignnone size-full wp-image-247530\" src=\"https://www.dummies.com/wp-content/uploads/GED_0801.jpg\" alt=\"GED_0801\" width=\"111\" height=\"45\" />\r\n\r\nSubstitute the given shadow length of the tree into the proportion and let <em>x</em> equal the unknown height of the tree:\r\n\r\n<img class=\"alignnone size-full wp-image-247531\" src=\"https://www.dummies.com/wp-content/uploads/GED_0802.jpg\" alt=\"GED_0802\" width=\"71\" height=\"45\" />\r\n\r\nMultiply both sides by 33 to solve for <em>x:</em>\r\n\r\n<img class=\"alignnone size-full wp-image-247532\" src=\"https://www.dummies.com/wp-content/uploads/GED_0803.jpg\" alt=\"GED_0803\" width=\"97\" height=\"79\" />\r\n\r\nAlternatively, you can solve the proportion by cross-multiplying and then dividing both sides by 5:\r\n\r\n<img class=\"alignnone size-full wp-image-247533\" src=\"https://www.dummies.com/wp-content/uploads/GED_0804.jpg\" alt=\"GED_0804\" width=\"85\" height=\"49\" />\r\n\r\nChoice (A) is the correct answer.</li>\r\n \t<li>The correct answer is D.\r\n\r\nSet up a proportion with minutes as the numerator of the fraction and the number of laps as the denominator:\r\n\r\n<img class=\"alignnone size-full wp-image-247534\" src=\"https://www.dummies.com/wp-content/uploads/GED_0805.jpg\" alt=\"GED_0805\" width=\"101\" height=\"49\" />\r\n\r\nSubstitute the given number of laps into the proportion, letting <em>x</em> equal the unknown number of minutes:\r\n\r\n<img class=\"alignnone size-full wp-image-247535\" src=\"https://www.dummies.com/wp-content/uploads/GED_0806.jpg\" alt=\"GED_0806\" width=\"61\" height=\"45\" />\r\n\r\nMultiply both sides by 10 to solve for <em>x,</em> giving you <em>x</em> = 27.5.\r\n\r\nAlternatively, you can solve the proportion by cross-multiplying and then dividing both sides of the equation by 4:\r\n\r\n<img class=\"alignnone size-full wp-image-247536\" src=\"https://www.dummies.com/wp-content/uploads/GED_0807.jpg\" alt=\"GED_0807\" width=\"88\" height=\"77\" />\r\n\r\nHence, Choice (D) is the correct answer.</li>\r\n</ol>","description":"One or two questions on the GED Math test will ask you to find an unknown quantity of something, using a proportional relationship. The following practice questions ask you to do this by setting up a proportion where you are given three related values and you have to find the missing fourth value.\r\n<h2 id=\"tab1\" >Practice Questions</h2>\r\n<ol>\r\n \t<li>On a sunny day, a tree casts a shadow that is 33 feet long. At the same time, a nearby 4-foot-tall mailbox casts a shadow that is 5.5 feet long. What is the height of the tree? Round your answer to the nearest foot.\r\n\r\n<strong>A.</strong> 24 feet\r\n<strong>B.</strong> 33 feet\r\n<strong>C.</strong> 38 feet\r\n<strong>D.</strong> 45 feet</li>\r\n \t<li>Meg can swim 4 laps in 11 minutes. How long should she plan to practice if she needs to swim 10 laps, assuming her speed is constant?\r\n\r\n<strong>A.</strong> 4.4\r\n<strong>B.</strong> 15.7\r\n<strong>C.</strong> 22\r\n<strong>D.</strong> 27.5</li>\r\n</ol>\r\n<h2 id=\"tab2\" >Answers and Explanations</h2>\r\n<ol>\r\n \t<li>The correct answer is A.\r\n\r\nSet up a proportion for the mailbox with the height as the numerator of the fraction and the shadow length as the denominator:\r\n\r\n<img class=\"alignnone size-full wp-image-247530\" src=\"https://www.dummies.com/wp-content/uploads/GED_0801.jpg\" alt=\"GED_0801\" width=\"111\" height=\"45\" />\r\n\r\nSubstitute the given shadow length of the tree into the proportion and let <em>x</em> equal the unknown height of the tree:\r\n\r\n<img class=\"alignnone size-full wp-image-247531\" src=\"https://www.dummies.com/wp-content/uploads/GED_0802.jpg\" alt=\"GED_0802\" width=\"71\" height=\"45\" />\r\n\r\nMultiply both sides by 33 to solve for <em>x:</em>\r\n\r\n<img class=\"alignnone size-full wp-image-247532\" src=\"https://www.dummies.com/wp-content/uploads/GED_0803.jpg\" alt=\"GED_0803\" width=\"97\" height=\"79\" />\r\n\r\nAlternatively, you can solve the proportion by cross-multiplying and then dividing both sides by 5:\r\n\r\n<img class=\"alignnone size-full wp-image-247533\" src=\"https://www.dummies.com/wp-content/uploads/GED_0804.jpg\" alt=\"GED_0804\" width=\"85\" height=\"49\" />\r\n\r\nChoice (A) is the correct answer.</li>\r\n \t<li>The correct answer is D.\r\n\r\nSet up a proportion with minutes as the numerator of the fraction and the number of laps as the denominator:\r\n\r\n<img class=\"alignnone size-full wp-image-247534\" src=\"https://www.dummies.com/wp-content/uploads/GED_0805.jpg\" alt=\"GED_0805\" width=\"101\" height=\"49\" />\r\n\r\nSubstitute the given number of laps into the proportion, letting <em>x</em> equal the unknown number of minutes:\r\n\r\n<img class=\"alignnone size-full wp-image-247535\" src=\"https://www.dummies.com/wp-content/uploads/GED_0806.jpg\" alt=\"GED_0806\" width=\"61\" height=\"45\" />\r\n\r\nMultiply both sides by 10 to solve for <em>x,</em> giving you <em>x</em> = 27.5.\r\n\r\nAlternatively, you can solve the proportion by cross-multiplying and then dividing both sides of the equation by 4:\r\n\r\n<img class=\"alignnone size-full wp-image-247536\" src=\"https://www.dummies.com/wp-content/uploads/GED_0807.jpg\" alt=\"GED_0807\" width=\"88\" height=\"77\" />\r\n\r\nHence, Choice (D) is the correct answer.</li>\r\n</ol>","blurb":"","authors":[{"authorId":8947,"name":"The Experts at Dummies","slug":"the-experts-at-dummies","description":"The Experts at Dummies are smart, friendly people who make learning easy by taking a not-so-serious approach to serious 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GED Math Extra Prep: Proportions

By: The Experts at Dummies and

Updated: 11-29-2017

From The Book: GED Test

GED Test

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One or two questions on the GED Math test will ask you to find an unknown quantity of something, using a proportional relationship. The following practice questions ask you to do this by setting up a proportion where you are given three related values and you have to find the missing fourth value.

Practice Questions

On a sunny day, a tree casts a shadow that is 33 feet long. At the same time, a nearby 4-foot-tall mailbox casts a shadow that is 5.5 feet long. What is the height of the tree? Round your answer to the nearest foot.
A. 24 feet B. 33 feet C. 38 feet D. 45 feet
Meg can swim 4 laps in 11 minutes. How long should she plan to practice if she needs to swim 10 laps, assuming her speed is constant?
A. 4.4 B. 15.7 C. 22 D. 27.5

Answers and Explanations

The correct answer is A.
Set up a proportion for the mailbox with the height as the numerator of the fraction and the shadow length as the denominator:
Substitute the given shadow length of the tree into the proportion and let x equal the unknown height of the tree:
Multiply both sides by 33 to solve for x:
Alternatively, you can solve the proportion by cross-multiplying and then dividing both sides by 5:
Choice (A) is the correct answer.
The correct answer is D.
Set up a proportion with minutes as the numerator of the fraction and the number of laps as the denominator:
Substitute the given number of laps into the proportion, letting x equal the unknown number of minutes:
Multiply both sides by 10 to solve for x, giving you x = 27.5.
Alternatively, you can solve the proportion by cross-multiplying and then dividing both sides of the equation by 4:
Hence, Choice (D) is the correct answer.

About This Article

This article is from the book:

GED Test ,

About the book author:

Stuart Donnelly, PhD, earned his doctorate in mathe-matics from Oxford University at the age of 25. Since then, he has established successful tutoring services in both Hong Kong and the United States and is considered by leading educators to be one of the most experienced and qualified private tutors in the country.

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GED ,