write the following complex number in polar form. Express all angles in degrees rounded to the nearest tenth.

r = sqrt ( 2^2 + (√21)^2 ) = sqrt ( 4 + 21) = sqrt (25) = 5

θ = arctan ( √21 / 2) ≈ 66.4°

5cos(66.4°) + 5i sin (66.4°) = 5 [ cos (66.4° + i sin (66.4° ) ]