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Put the calculator in Radian mode.
Press [MODE], use the arrow keys to highlight RADIAN, and then press [ENTER].
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If necessary, press [2nd][MODE] to access the Home screen.
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Enter the number of degrees.
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Press [2nd][APPS][1] to paste in the degree function.
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Press [ENTER] to convert the degree measure to radians.
This is illustrated in the first screen.
If you’re a purist who likes to see radian measures expressed as a fractional multiple of pi whenever possible, continuing with the following steps accomplishes this goal if it’s mathematically possible.
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To divide the radian measure by pi, press
This is illustrated in the second screen.
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Press [MATH][ENTER][ENTER] to convert the result to a fraction, if possible.
This is illustrated in the third screen. If the calculator can’t convert the decimal obtained in Step 6 to a fraction, it says so by returning the decimal in Step 7.
To convert radians to degrees:
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Put the calculator in Degree mode.
Press [MODE], use the arrow keys to highlight DEGREE, and then press [ENTER].
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If necessary, press [2nd][MODE] to access the Home screen.
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Enter the radian measure.
If the radian measure is entered as an arithmetic expression, surround that expression with parentheses.
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Press [2nd][APPS][3] to paste in the r function.
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Press [ENTER] to convert the radian measure to degrees.
This is illustrated in the first screen.
The TI-84 Plus is a complicated tool and it's easy to make mistakes on it. For more help, check out 10 Common Errors When Using the TI-84 Plus Calculator.