Question

Найдите площадь боковой поверхности правильной девятиугольной пирамиды, если ее апофема равна 4 см, а сторона основания 2 см

Answer 1

Ответ:

36см²

Объяснение:

Sбок=1/2*Росн*l, где Росн- периметр основания; l-апофема.

Росн=2*9=18 см периметр девятиугольника.

Sбок=1/2*18*4=36см²

Answer 2

Calculation of the lateral surface area of a regular nonagon pyramid

To find the lateral surface area of a regular nonagon pyramid, we need to know the apothem and the side length of the base.

Given: - Apothem (a) = 4 cm - Side length of the base (s) = 2 cm

To calculate the lateral surface area, we can use the formula:

Lateral Surface Area = (Perimeter of the base) x (Apothem) / 2

The perimeter of the base can be calculated by multiplying the number of sides (n) by the side length (s) of the base. In this case, since we have a nonagon (9-sided polygon), n = 9.

Let's calculate the perimeter of the base first:

Perimeter of the base = n x s = 9 x 2 = 18 cm

Now, we can calculate the lateral surface area:

Lateral Surface Area = (18 cm) x (4 cm) / 2 = 36 cm²

Therefore, the lateral surface area of the given regular nonagon pyramid is 36 cm².