Answer:
C. 42
Step-by-step explanation:
<em>Since the triangle making up the base of the right triangular pyramid is equilateral, the three lateral triangles will have equal areas. To find the surface area of the pyramid, find the area of one of the lateral triangles and multiply it by 3. Then, add that to the area of the triangle that forms the base.</em>
<em>Area of Lateral Triangle = 1/2 · base · height</em>
<em> = 1/2 · X · Z</em>
<em> = 1/2 · 4 units · 6 units</em>
<em> = 12 square units</em>
<em>Area of Base Triangle = 1/2 · base · height</em>
<em> = 1/2 · X · Y</em>
<em> = 1/2 · 4 units · 3 units</em>
<em> = 6 square units</em>
<em>Now, use the method described above to find the surface area of the pyramid.</em>
<em>Surface Area = 3( Area lateral ) + ( Area base )</em>
<em> = 3 ( 12 square units ) + ( 6 square units )</em>
<em> = 42 square units</em>
