Answer:
These two triangles are similar triangles. This means that their side lengths are proportional to each other.
Thus, making line segment EC equal to "x", and BC equal to "y" we can write:
8/y = 28/(10+y)
The next step is to get rid of the fractions, which can be done by cross multiplying.
So we have:
8(10+y) = 28(y)
After distribution and some simplification, you should get the value of y.
80+8y = 28y
80 = 20y
80/20 = 20y/20
4 = y
y = 4
Knowing that y = BC, and y = 4, it is clear that BC = 4.
Since BC = 4, one can use the Pythagorean Theorem to solve for segment EC.
Pythagorean Theorem: a^2 + b^2 = c^2, where a and b are the side lengths of a right triangle, and c is the hypotenuse (in other words the longest side)
In our case, a and b are 8 and 4 (the order doesn't really matter here).
So we have: 8^2 + 4^2 = c^2
64 + 16 = c^2
80 = c^2
c = sqrt 80
c = 4 sqrt 5
And we arrive at the answer- EC = 4 sqrt 5, making B the correct choice.
Hope this helps!
