Question

Ming drew a triangle. The sum of the angles of the triangle is 180º. In Ming’s triangle, mc025-1.jpgB is twice the measure of mc025-2.jpgA, and angle mc025-3.jpgC is 5º greater than four times mc025-4.jpgA. The system of equations below can be used to find the measure of the three angles, where a represents the measure of mc025-5.jpgA, b represents the measure of mc025-6.jpgB, and c represents the measure of mc025-7.jpgC.

a + b + c = 180
2a = b
4a + 5 = c


Which matrix represents the measure of each angle in Ming’s triangle?

Answer 1

From 2a = b and c = 4a + 5, substitute into a + b + c = 180:
a + 2a + (4a + 5) = 180 → 7a + 5 = 180 → a = 25.
Then b = 2a = 50 and c = 4a + 5 = 105.

Matrix (column) =
[25
50
105]