Question

The numbers are measurements of radius diameter and circumference of circles A and B. Circle A is smaller than Circle B which number belongs to which quantity? 2.5, 5, 7.6, 15.2, 15.7, 47.7

Answer 1

Explanation:

a diameter is always twice the radius.

the only pairs in this list, where one number is twice the other, is :

2.5 and 5

7.6 and 15.2

so,

2.5 is the radius of A

5 is the diameter of A

7.6 is the radius of B

15.2 is the diameter of B

15.7 is then the circumference of A (as the smaller of the remaining 2 numbers).

47.7 is the circumference of B.

this is also proven by the formula for the circumference of a circle : c = 2×pi×r