Question

find the diameter whose circumference is 77

Answer 1

c = 77

2πr = 77
2 × 22/7 × r = 77
r = 77 × 7/ 44
r = 12.25

d = 2r
d = 2 × 12.25
d = 24.5

Answer 2

the formula of circumference is
$2\pi \: r$
So,
$2\pi \: r = 77 \\ 2 \times 22 \div 7 \times r = 77 \\ r = 77 \times 7 \div 22 \times 1 \div 2 \\ r = 49 \div4 \\ diamter \: = 49 \div 4 \times 2$


answer is 49\2