Question

Enter the number that belongs in the green box

Answer 1

Set your calculator to Degree mode.

10² = 6.78² + 4² - 2(6.78)(4)(cos x)

100 = 61.9684 - 54.24(cos x)

38.0316 = -54.24(cos x)

cos x = -.701173

`x = {cos}^( - 1) ( - .701173)`

x = 134.52°