Question

Find the cosine of each acute angle in the triangle below. Select all that apply.

Answer 1

In the given triangle by using Pythagoras theorem ,

`\begin{gathered} 17^2=x^2+8^2 \\ x^2=17^2-8^2 \\ x^2=\text{ 289 - 64} \end{gathered}`

Further,

`\begin{gathered} x^2\text{ = 225} \\ x\text{ = }\sqrt[]{225} \\ x\text{ = 15 units } \end{gathered}`

Cosine of the acute angle is calculated as,

`\begin{gathered} \cos (\theta_1)\text{ = }(15)/(17) \\ \end{gathered}`

and

`\cos (\theta_2)\text{ = }(8)/(17)`

Thus the required answer is ,

`\begin{gathered} \cos (\theta_1)\text{ = }(15)/(17) \\ \cos (\theta_2)\text{ = }(8)/(17) \end{gathered}`