Question

Из жести сделан бак БЕЗ КРЫШКИ.Он имеет форму прямоугольного параллелепипеда длиной 90 см,шириной 50 см и высотой 70 см.Бак надо покрасить СНАРУЖИ и ИЗНУТРИ.Какую площадь надо покрасить?

Answer 1

Calculation of the Surface Area of the Tank

To determine the surface area that needs to be painted, we need to calculate the total surface area of the rectangular parallelepiped tank. The surface area of a rectangular parallelepiped can be calculated using the formula:

Surface Area = 2lw + 2lh + 2wh

where: - l is the length of the tank (90 cm) - w is the width of the tank (50 cm) - h is the height of the tank (70 cm)

Let's substitute the given values into the formula:

Surface Area = 2(90 cm * 50 cm) + 2(90 cm * 70 cm) + 2(50 cm * 70 cm)

Calculating the values:

Surface Area = 2(4500 cm²) + 2(6300 cm²) + 2(3500 cm²)

Surface Area = 9000 cm² + 12600 cm² + 7000 cm²

Surface Area = 28600 cm²

Therefore, the total surface area of the tank that needs to be painted, both inside and outside, is 28600 cm².