The answer is A.
But that is not the exact answer as 3.14 is not exactly equal to pi but that's the best we can do when theres a billion digits of pi
hmmm let's find the distance between B and C first off.

hmmm if BC is that much, then AB + AC = 7, since AB + AC + BC = 12 which is the perimeter, Check the picture below.
Answer:
Step-by-step explanation:
Given that :
Radiant energy produced per second = 3.9 * 10^33 ergs
Amount of radiant energy produced in (t) = 3.25 * 10^3 s
Radiant energy per second * time
(3.9 * 10^33) * (3.25 * 10^3)
12.675 * 10^(33 + 3)
12.675 * 10^36 ergs
= 1.2675 * 10^37 ergs
Reasonable distance for measuring tracks on a railroad:
1.435 ⋅ 10−3 mm or 1.435 ⋅ 103 mm?
1.435 × 10^-3 mm = 0.001435 mm
1.435 × 10^3 mm = 1435mm
1.435 × 10^3 mm seems more reasonable