A complex number 21 has a magnitude 21 = 2 and an angle 01 = 39°.
Express 21 in rectangular form, as 21
= a + bi.
Round a and b to the nearest thousandth.

Where is the diagram

Add the cents that add the left overs to get the first number

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square