The radius of a circle is 8 kilometers. What is the length of a 90° arc?

To answer, you need the circumference, and a 90 degree arc is just 1/4 of that circumference (360/90).

C=pi(D)
C=pi(16) (16 because diameter is just 2x the radius, which is 8)
C=16pi

So, divide this by 4, and the arc will be 4pi.

I'll do the first one for you. it isn't very hard at all.on number one, you have (50 × 3), which equals 150, and (3 × 3), which equals 9. after you establish that, you add 150 and 9 together. so, (150 + 9) equals 159.this means that 53 × 3 = 159.