The surface area of the pyramid is 429 cm²
The surface area of a pyramid is calculated by adding the area of the base with the area of the the triangular faces .
The pyramid above is a square based pyramid and thus it will have 4 triangular faces.
Area of the base = 11²
= 11 × 11 = 121 cm²
Area of the triangle = 1/2bh
= 1/2 × 11 × 14
= 77 cm²
for 4 triangles
= 4 × 77
= 308 cm²
Surface area of the pyramid = 308 + 121
= 429 cm²