Well u do 31.2 x 18 which is 561.6 then u divide by 2 because the formula for a triangle is base x height divided by 2 so It is 280.8
1 and 1/9 I Checked it on a calculator
Answer:
C) 80
Step-by-step explanation:
triangles always add up to 180 degrees, so 80+20=100 the missing angle is 80 degrees
