Question

What is the value of x

Answer 1

Check the picture below.

`\cos(x )=\cfrac{\stackrel{adjacent}{15}}{\underset{hypotenuse}{21}}\implies \cos(x)=\cfrac{5}{7}\implies x=\cos^(-1)\left( \cfrac{5}{7} \right)\implies x\approx 44^o`

Make sure your calculator is in Degree mode.

Answer 2

≈ 44°

The correct answer is the second one

Explanation:

Use trigonometry:

`\cos(x°) = (15)/(21)`

Use the reverse function (SHIFT, cos) on your calculator to find x:

`x≈44°`