Angle A of an isoceles triangle ABC measures 20 degrees more than three times angle B. Find the measure of angle C.
In an isosceles triangle two angles are equal. The measure of angle A is 20 degrees more than three times angle B. Angle B has the same measure as angle C.
The sum of the three angles is 180 degrees. If the measure of angle C is X.
X + X + 3*X + 20 = 180
=> 5X = 160
=> X = 32
The measure of angle C is 32 degrees.
Sum of 3 angles of a triangle = 180 degrees
In isoceles triangle base angles are equal
i.e. M angle B = M angle C = x, say
Let y be the M angle A, the vetrex angle
y+2x = 180, sum of three angles ..........(1)
and y is 20 dgrees more than three times Measure angle B
i.e. y = 20+3x
substituting value of y in (1) we get
20+3x+2x = 180
3x+2x = 180-20
5x = 160
x = 160/5 = 32 dgrees
Measure angle C = 32 degrees