Question

The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times the measure of the first angle. The third angle is 10 more than the second.

Answer 1

first angle be 30°

second angle be 70°

third angle be 80°

Explanation:

first angle be x

second angle be y

third angle be z

x+y+z=180

given, y+z = 5x; z=5x-y

also, z=y+10

5x-y = y+10

5x= 10+y+y = 10+2y

x= (10+2y)/5

x+y+z=180

(10+2y)/5 + y + y+10 = 180

(10+2y)/5 = 180 -2y -10

(10+2y)/5 = 170-2y

multiply both sides by 5

10+2y = 5(170-2y)

10+2y= 850-10y

2y+10y = 850-10

12y= 840

y= 840/12 = 70°

z=y+10 =70+10= 80°

5x= (10+2y) = 10+2(70) = 10+140= 150

x = 150/5 = 30°