The side length of the two bottom surfaces of a regular triangular pyramid is 30cm and 20cm respectively, and the side area is equal to the sum of the two bottom areas

The side length of the two bottom surfaces of a regular triangular pyramid is 30cm and 20cm respectively, and the side area is equal to the sum of the two bottom areas

Let ABC be the ground of the triangular pyramid
The bottom is a'b'c '
Take the midpoint d e of BC b'c 'to connect
Then the quadrilateral deaa 'is trapezoid
Its height is the height of the pyramid, and its waist is the height of the side
Then 0.5 (30 * 15 √ 3) + 0.5 (20 * 10 √ 3) = 3 * 0.5 (20 + 30) * X
x=13√3/3
There is Pythagorean theorem, H = √ (X & # 178; - (5 √ 3 / 3) &# 178;) = 4 √ 3cm