Answer:
406.3 cm²
Step-by-step explanation:
The total surface area is the sum of the base area and the lateral area. The lateral area is the sum of the areas of the 6 congruent triangular faces.
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lateral area
Each triangular face has a base of 8 cm and a slant height of 10 cm. Its area is ...
A = 1/2bh
A = 1/2(8 cm)(10 cm) = 40 cm²
Then the area of 6 faces is 6×40 cm² = 240 cm².
total area
The base area is given.
The total area is the sum of the lateral area and the base area:
total area = 240 cm² +166.3 cm² = 406.3 cm²
The surface area is about 406.3 cm².
