Question

the perimeter of the base of the regular triangular pyramid is p = 16.5 cm. find the sum of all edges of this pyramid, if the perimeter of a lateral face is 18.5 cm

Answer 1

36 cm

Explanation:

The sum of the perimeters of three lateral faces will count each "lateral" edge twice and the base edges once. Adding the base perimeter to that product will count every edge twice, so the total of all edge lengths is ...

(3(18.5 cm) +16.5 cm)/2 = 72 cm/2 = 36 cm . . . . sum of all edge lengths