Question

Enter the number that belongs in the green box

Answer 1

28.21°

Explanation:

use the Cosine rule (Cos A = (b² + c² - a²) / 2bc)

let's call our angle A.

then Cos A = (12² + 20² - 11²) / (2 X 12 X 20)

= 141/160.

A = Cos^-1 (141/160)

= 28.21° to nearest hundredth