In △ABC , m∠A=63° and m∠C=99°. What is the measure of angle B?
We know that the sum of the angles in a triangle is always 180°.
Therefore, the measure of angle B can be found by subtracting the measures of angles A and C from 180°.
m∠B = 180° - m∠A - m∠C
m∠B = 180° - 63° - 99°
m∠B = 18°
To find the measure of angle B in triangle ABC, we can use the fact that the sum of the angles in a triangle is always 180 degrees.
Step 1: Add the known angle measures.
m∠A = 63°
m∠C = 99°
Step 2: Add the measures of angles A and C.
m∠A + m∠C + m∠B = 180°
63° + 99° + m∠B = 180°
Step 3: Simplify the equation.
162° + m∠B = 180°
Step 4: Solve for m∠B.
m∠B = 180° - 162°
m∠B = 18°
So, the measure of angle B is 18 degrees.