Question

How do I solve both those questions?

Answer 1

Answer:

See below

Step-by-step explanation:

9. Length of arc of circle, given central angle of measure n (in radians):

$s = \dfrac{n}{2 \pi} 2 \pi r$

which simplifies to

$s = nr$

For n = pi/4:

s = pi/4 * 5 = 1.25 pi = 3.92...

For n = pi/2:

s = pi/2 * 5 = 2.5 pi = 7.85...

Integer values between 3.92 and 7.85 are 4, 5, 6, and 7.

Pick one of them.

10. The square you drew will help.

The area of the shaded region is the area of the square minus the area of the 4 quarter circles inside the square. Four quarter circles amount to a full circle.

The square has side 8 which is the same as twice the radius of a circle.

shaded area = area of square - area of circle

shaded area = s^2 - pi r^2

shaded area = 8^2 - pi * 4^2

shaded area = 64 - 16pi