Answer: 175 cm²
Explanation:
 Since there are four congruent triangles, we will find the area of one and multiply by 4:
A = 

A = 

A = 31.5 cm²
-
31.5 cm² * 4 = 126 cm²
 Now, we will find the area of the center square:
A = L²
A = 7²
A = 49 cm²
 Lastly, we will find the total surface area:
126 cm² + 49 cm² = 175 cm²
 The surface area of this square pyramid is 175 cm.