We can use the pythagorean theorem to solve this
The pythagorean theorem = a^2 + b^2 = c^2, while
a = one leg
b = the second leg
c = the hypotenuse
In this problem,
a = 3
b = 15
c = ?
Let's plug our values into the pythagorean theorem
(3)^2 + (15)^2 = c^2
9 + 225 = c^2
Add together the left side
234 = c^2
Take the sqrt of both sides
sqrt(234) = c
The length of BC = sqrt(234)
