Answer: 175 cm²
Explanation:
Since there are four congruent triangles, we will find the area of one and multiply by 4:
A =
![(B*H)/(2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/oe4n5b83xhvc9n4fjo3293ygdz93zv91ul.png)
A =
![(7*9)/(2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/pez9zbjwdvl4rrtts4ci0f6tbeek8lvt6o.png)
A = 31.5 cm²
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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.