Dwayne is finding the base of the triangle shown. It's area is 100 square meters. find his mistake and correct it.

His mistake is in the formula for Area of triangle. The correct formula is:
[tex] A= \frac{1}{2}(base)(height) [/tex]
Given that, Area= 100 sq. meter and height = 20 meter
So,
[tex] 100 = \frac{1}{2}(base)(20)\\ \\ 100 = (base)(10)\\ \\ base = \frac{100}{10}=10 [/tex]
So, the base of the triangle will be 10 meter.