Answer:
the y intercept
Step-by-step explanation:
the k in algebra is the y intercept :))
For the first one write 9 divided by 2 gives your your radius an it’s 3.5. the formula is 2 x 3.14 x radius and that gives you 21.98.
the 2nd one is 2 x 3.14 x 9 = 56.52
the 3rd is 2 x 3.14 x 5= 31.4
formula is always 2 x 3.14 (or pie) x radius
to get your radius from your diameter you do your diameter divided by 2
