First it’s your gonna need to find the area of the triangle.
Area of triangle = 1/2 base x height
= (1/2 15) x 20
= 7.5 x 20
= 150 m square
Then we are gonna multiply the area of the triangle by 2 because there are two triangles making up this object.
= 150 m square x 2
= 300 square
Then we are gonna find the area of the rectangles
Area of rectangle 1 = length x width
= 7 x 25
= 175 m square
Area of rectangle 2 = 7 x 20
= 140 m square
Area of rectangle 3 = 15 x 7
= 105 m square
Then your gonna add all the area of the rectangles.
= 175 + 140 + 105= 420 m square
Then we are gonna add both the area of the triangles and the area of the rectangles and that would conclude the surface area.
300 m square + 400 m square = 700 m square
Therefore the surface area is 700 m square