Question

POSSIBLE POINTS: 50

BEE
The sum of interior angles in a triangle are 180 degrees. Angle B and C are congruent. Angle B is
twenty less than angle A. Write and solve a system of equations using substitution.

Answer 1

A = 73.33

B = 53.33

C = 53.33

Explanation:

Since they are in a triangle, the sum of the three angles = 180

A + B + C = 180 ••••••(i)

Since B and C are congruent, it means that they are equal;

hence B = C ••••••(ii)

We can rewrite equation i as;

A + B + B = 180

A + 2B = 180 ••••••(iii)

Lastly;

B = A -20 •••••(iv)

Substitute iv into iii

A + 2(A -20) = 180

A + 2A -40 = 180

3A = 180 + 40

3A = 220

A = 220/3 = 73.33

But B = C = A -20 = 73.33 -20 = 53.33