Answer:
45m
Step-by-step explanation:
3*4.5 =13.5
7*4.5= 31.5
13.5+31.5= 45m
(you would do 4.5 because each triangles length is only half of the 9m across. you also would not have to divide by 2 like you usually would when finding the area of a triangle becuase there are 2 congruent triangles)
