11-2m-(n+5+(-m)-3n+8)
11-2m-n-5-m+3n-8
Answer: -2-3m+2n
Step-by-step explanation:
Draw lines from one vertex to the other vertices, splitting the polygon into triangles. If the polygon has n sides, there will be n−2 triangles. Each triangle's angles add up to 180°. So the sum of all the interior angles is:
S = (n−2) 180°
Answer:
area of trapezium:
a+b divided by 2, times by the height.
so its 8+20=28.
28/2=14.
14*14=196.
area=196
Step-by-step explanation: