Step-by-step explanation:
So here...two triangle is measured in 78° and 30° ..here to find the value of third angle...
we need to subtract 180° from the sum of 78° and 30° ...cause the sum of all angle of triangle is 180° ..
x + 78° + 30° = 180°
x + 108° = 180°
x = 180° - 108°
x = 72°
hence the value of third angle is 72°....
