Assuming that the triangle is a right triangle, we can reverse engineer the Pythagorean theorem (a^2+b^2=c^2).
60^2 + x^2 = 61^2
3600 + x^2 = 3721
x^2 = 3600 - 3721
x^2 = 121
x = sqrt121
x = 11
Answer:
72.25663
Step-by-step explanation:
C=2πr=2·π·11.5≈72.25663