15 cm 15 cm
10 cm
10 cm
1
10 cm
1
8.66cm
1
The surface area of the three-dimensional figure is
square centimeters.
Picture is quite a bit more helpful

Total surface area = 536.6 cm²

Step-by-step explanation:

Surface area of the given figure = Area of rectangle (1) + Area of rectangle (2) + Area of rectangle (3) + Area of triangle (4) + Area of triangle (5)

Area of rectangle (1) = Length × Width

                                  = 10 × 15

                                  = 150 cm²

Area of rectangle (2) = 10 × 15

                                   = 150 cm²

Area of rectangle (3) = 10 × 15

                                   = 150 cm²

Area of triangle (4) =

                               =

                               = 43.3 cm²

Area of triangle (5) =

                               = 43.3 cm²

Total surface area = 150 + 150 + 150 + 43.3 + 43.3

                               = 536.6 cm²

1/4 because there is 4 grades.