Question

In the diagram below, if the measure of < C = 45 °, and side AC = 10, then side BC = _____.

Answer 1

Given:

Using the trigonometric ratio of cosine,

`\begin{gathered} cos\theta=(adjacent)/(hypotenuse) \\ cos45=(BC)/(10) \\ BC=10* cos\text{ 45} \\ BC=10*(√(2))/(2) \\ BC=5√(2) \end{gathered}`

Therefore, OPTION A is correct.