The side of the base of a regular quadrangular pyramid is 2 cm. The side edges are inclined to the base plane at an angle
The side of the base of a regular quadrangular pyramid is 2 cm. The side edges are inclined to the base plane at an angle of 45 degrees. Find the volume of the pyramid.
Determine the area of the base of the pyramid. Sbn = AB ^ 2 = 2 ^ 2 = 4 cm2.
Since the pyramid is regular, there is a square at its base, and all the side edges are equal.
In a right-angled triangle ACD, AD = CD = 2 cm.
Then, by the Pythagorean theorem, AC ^ 2 = 2 * AD ^ 2 = 2 * 4 = 8.
AC = 2 * √2 cm.
The diagonals of the square are equal and the point of their intersection is divided in half, then CO = AC / 2 = 2 * √2 / 2 = √2 cm.
In a right-angled triangle KOC, the angle OCK = 450, then the triangle KOC is rectangular and isosceles, OK = OC = √2 cm.
Let’s define the volume of the pyramid.
V = Sbn * OK / 3 = 4 * √2 / 3 cm3.
Answer: The volume of the pyramid is 4 * √2 / 3 cm3.