Answer: 17
The more accurate value is roughly x = 16.5482258257411
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Work Shown:
cos(angle) = adjacent/hypotenuse
cos(38) = x/21
21*cos(38) = x
x = 21*cos(38)
x = 16.5482258257411 which is approximate
x = 17
I'm rounding to the nearest whole number since the other side (21) is a whole number. If your teacher instructs you to round otherwise, then follow those instructions of course. Make sure your calculator is in degree mode.
