what’s the problems to solve?!?!

Answer:
84 cm
Step-by-step explanation:
To find surface area, you must find the area and add all sides:
Large rectangle = 10x4 = 40cm
Small rectangle = 10x3 = 30cm
2x Triangles = 4x3 = 12x2(for 2 triangles) = 24cm
40 + 30 + 24 = Answer