Answer:
248.95 square centimetres
Step-by-step explanation:
The surface area of a 3D figure is the sum of the areas of the exterior surfaces.
Here, we have one equilateral triangle as the base with base 13 and height 11.3. We also have three other congruent lateral triangles with base 13 and height 9.
The area of a triangle is denoted by A = (1/2) * bh, where b is the base and h is the height.
The area of the base triangle is:
A = (1/2) * bh
A = (1/2) * 13 * 11.3 = 73.45 cm²
The area of one lateral triangle is:
A = (1/2) * bh
A = (1/2) * 13 * 9 = 58.5 cm²
Since there are 3 such triangles, multiply 58.5 by 3:
58.5 * 3 = 175.5 cm²
Finally, add 175.5 to 73.45:
175.5 + 73.45 = 248.95 cm²
The answer is thus 248.95 square centimetres.
<em>~ an aesthetics lover</em>
