what is the value of x
find the value of f

Answer:
x = 20°
f = 40°
Step-by-step explanation:
4x + 5x = 180°
because a straight line is 180°
so 9x = 180°
1x = 180 ÷ 9
1x = 20
all angles in a triangle add together is 180°
so 7x + f = 180°
1x = 20
7x = 20 × 7
7x = 140°
f = 180° - 140 °
f = 40°
Answer:
x = 20 , f = 40
Step-by-step explanation:
4x and 5x are a linear pair and sum to 180° , then
4x + 5x = 180
9x = 180 ( divide both sides by 9 )
x = 20
then
5x = 5 × 20 = 100° and 3x = 3 × 20 = 60°
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
5x is an exterior angle of the triangle , then
f + 3x = 5x , that is
f + 60 = 100 ( subtract 60 from both sides )
f = 40