Question

Not able to find this answer pls help

Answer 1

Step-by-step explanation:

(a)

Radius of arc ACB is = 10 cm so

We know length of arc

$l = r \theta = 10 \times \frac{\pi}{3} = \frac{10\pi}{3} \: cm$

(b)

Think of required area as difference between area of two pizza slices of 10 cm and 8 cm .

Let use elementary method to find area of one pizza slice of angle π/3 .

We know that area for total circle of 2π is

$= \pi {r}^{2}$

So area for angle π/3 will be

$\frac{\pi {r}^{2} }{2\pi} \times \frac{\pi}{3} = \frac{\pi {r}^{2} }{6}$

So difference will be

$= \frac{\pi}{6} ( {10}^{2} - {8}^{2} ) \\ \\ = \frac{\pi}{6} (100 - 64) \\ \\ = 6\pi \: cm {}^{2} \: \: \: \: \: \: \: \:$