Question

c) y 68° 20.8 m

Explanation:

Step1: Identify the trigonometric ratio

We use the cosine function. $\cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}$. Here, $\theta = 68^{\circ}$, adjacent side is $y$, and hypotenuse is $20.8$ m. So, $\cos68^{\circ}=\frac{y}{20.8}$.

Step2: Solve for $y$

$y = 20.8\times\cos68^{\circ}$. We know that $\cos68^{\circ}\approx0.3746$. Then $y=20.8\times0.3746$.
$y = 20.8\times0.3746=7.8$ (rounded to 1 decimal place).

Answer:

$7.8$ m