Question

A smaller triangle is cut out of a larger triangle. The larger triangle is a right triangle with side lengths of 5 millimeters and 12 millimeters. The smaller triangle has side lengths of 4 millimeters and 3 millimeters.
What is the area of the shaded region?

21 mm2
24 mm2
42 mm2
48 mm2

Answer 1

Larger triangle area = 1/2 · 5 · 12 = 30 mm^2.
Smaller triangle area = 1/2 · 3 · 4 = 6 mm^2.
Shaded area = 30 − 6 = 24 mm^2.

Answer: 24 mm^2.