Question

find the area of the triangle with vertices (5, 15), (5, 6), and (9, 6).
note that you can draw in the scratch area below, but it is not part of the answer.
scratch area (not part of answer)
area:
square units

Explanation:

Step1: Find the base and height

The two points \((5,6)\) and \((9,6)\) have the same \(y -\)coordinate. So the base \(b\) of the triangle is \(|9 - 5|=4\). The two points \((5,15)\) and \((5,6)\) have the same \(x -\)coordinate. So the height \(h\) of the triangle is \(|15 - 6| = 9\).

Step2: Use the triangle area formula

The area formula for a triangle is \(A=\frac{1}{2}\times b\times h\). Substitute \(b = 4\) and \(h=9\) into the formula: \(A=\frac{1}{2}\times4\times9\). First, calculate \(4\times9 = 36\), then \(\frac{1}{2}\times36=18\).

Answer:

\(18\)