Answer:
57.25 cm²
Explanation:
You want the surface area of a triangular pyramid with base sides 5 cm and slant height 6.2 cm. The height of the base triangle is given as 4.3 cm.
Surface area
The surface area of the figure is the sum of the areas of the four triangles that make it up. Three of those are congruent.
Triangle area
The formula for the area of a triangle is ...
A = 1/2bh . . . . . . base b, height h
For all of the triangles in the figure, the base length is 5 cm. The total area is ...
total area = lateral area + base area
total area = 3(1/2·(5 cm)(6.2 cm)) + 1/2(5 cm)(4.3 cm)
total area = (5/2 cm)(3·6.2 +4.3) cm = 57.25 cm²
The surface area of the pyramid is 57.25 cm².