4.) A parachutist jumps at night into a target that is a circle 10.5 m in diameter.

The circle is marked by flares 1.57 m apart. How many flares are there?

There are 21 flares there

Step-by-step explanation:

Firstly, we need to know how large the circle is

To calculate how large the circle is, we need to know what the circumference of the circle is

Mathematically, the circumference of a circle = pi * D

where D is the diameter of the circle and pi = 22/7

Thus, the circumference of the circle = 22/7 * 10.5m = 33m

Now, to know the number of flares, we divide the circumference of the circle by the the distance between the flares

That would be 33/1.57 = approximately 21