Question

When Isaac became married, he weighed much less than he does today. His ring finger has a diameter of 1.25 inches, while it had a diameter of just 1 inch when he was married.
Assuming his ring is perfectly circular and fits his finger perfectly, by what percentage has Isaac's ring circumference increased from when he became married to the present day?
F. 20%
G. 25%
H. 28%
J. 30%
К. 33%

Answer 1

To find the percentage increase in Isaac's ring circumference, we need to compare the difference in the diameter of the ring finger when he was married and today.

The formula for the circumference of a circle is C = πd, where C is the circumference and d is the diameter.

When Isaac was married, the diameter of his ring finger was 1 inch, so the circumference was C1 = π(1) = π inches.

Today, the diameter of his ring finger is 1.25 inches, so the circumference is C2 = π(1.25) = 1.25π inches.

The percentage increase in the circumference is then:

((C2 - C1)/C1) × 100% = ((1.25π - π)/π) × 100%
= (0.25π/π) × 100%
= 25%

Therefore, Isaac's ring circumference has increased by 25% from when he became married to the present day.

Therefore, the correct answer is option G, 25%.