Question

Triangle ABC is isosceles.

Triangle A B C. Angle A is x degrees, angle B is 118 degrees, angle C is x degrees. Sides A B and B C are equal.


Which equation can be used to find the degree measure of Angle A?

118 = x + x

x + x + 118 = 180

118 + 180 = x + x

(x + x) minus 118 = 180

Answer 1

B: x + x + 118 = 180

Explanation:

Got it right on Ed.

Answer 2

x+x°+118° = 180°; x = 31°

Explanation:

Given an isosceles triangle of ABC where angle A is x°, angle B is 118°, angle C is x°. To get the measure of angle A, the following steps must be followed.

Sum of angle in a triangle is 180° as shown

∠A+∠B+∠C = 180°

∠A = 180°-(∠B+∠C)

Substituting the values of each angle in the expression to get ∠A we have;

∠A = 180°- (118°+x°)

Since ∠A = x

x = 180°- (118°+x°)

x = 180°-118°-x°

x+x°+118° = 180° (This gives the required equation)

To get x;

2x° + 118° = 180°

Subtracting 118° from both sides

2x° + 118°-118° = 180°-118°

2x°= 62°

x = 31°