Haruto says the area of the triangle can be calculated using the following formula: A= 1/2·circumference·radius

Use this fact to convince a friend that the area of a circle is A=π·r2.

step-by-step explanation:

given that ab is divided into equal parts as

ac, cd, de, ef, fg, gh, hi, ib.

from this we find that f is the midpoint of ab.

so using mid point formula we find

f = (3,7)

similarly considering fb, we get

h = mid point of fb = ((6,6) and g, mid point of fh is

g = (9/2, 13/2)

i is mid point of hb

so i =(15/2,11/2)

i think the answer is c sorry if it's wrong