Carcass wrote:
What is the perimeter of the figure above?
(A) 380
(B) 360
(C) 330
(D) 300
(E) 230
Kudos for the right answer and explanation
Draw a perpendicular line as follows:
From here, we have
two different ways to find the value of x
Approach #1: Recognize that 60 and 100 are each 20 times the lengths of the basic 3-4-5 right triangle.
That is (20)(3) = 60 and (20)(5) = 100
So,
x = (20)(4) =
80Approach #2: Apply the Pythagorean theorem
We get:
60² +
x² = 100²
Simplify: 3,600 + x² = 10,000
Subtract 3,600 from both sides to get: x² = 6,400
Solve:
x = 80At this point we can find the perimeter....
Perimeter = 60 + 70 + 100 + 80 + 70 =
380Answer: A
Cheers,
Brent