Calculate the total surface area of a regular quadrangular pyramid, each edge of which is 5 dm.

Since the pyramid is correct, there is a square at its base.

Determine the area of ​​the base of the pyramid.

Sbn = AB * AD = 5 * 5 = 25 cm2.

The side faces of the pyramid are four equal, equilateral triangles.

Determine the area of ​​one side face.

We apply the formula for the area of ​​an equilateral triangle S = a ^ 2 * √3 / 4, where a is the length of the side of the triangle.

Streug = 25 * √3 / 4 cm2.

Then S side = 4 * Streug = (25 * √3 / 4) * 4 = 25 * √3 cm2.

Determine the total area of ​​the pyramid.

Spol = Sside + Sbn = 25 * √3 + 25 = 25 * (1 + √3) cm2.

Answer: The total area of ​​the pyramid is 25 * (1 + √3) cm2.



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