In the middle of a cuboid with a length of 15cm, a width of 8cm and a height of 5cm, a round hole with a diameter of 6cm at the bottom is dug out. What is the surface area of the cuboid after digging out Please answer me quickly

In the middle of a cuboid with a length of 15cm, a width of 8cm and a height of 5cm, a round hole with a diameter of 6cm at the bottom is dug out. What is the surface area of the cuboid after digging out Please answer me quickly

Original area = 15x8x2 + 8x5x2 + 15x5x2 = 470 square cm
Area of two circles excavated = 3.14x6x6x2 = 226.08 square cm
Increase circle side area = 3.14x6x2x5 = 188.4 square cm
Final area = 470-226.08 + 188.4 = 432.32 square cm

The rectangle is 3xcm in width and 6cm in width, and the trapezoid is 2xcm in upper bottom length, twice as long as the upper bottom length and 5cm in height. Which one has the largest area? How much?

Rectangular area = 18xcm ^ 2
Trapezoid area = (2x + 4x) * 5 / 2 = 30x / 2 = 15xcm ^ 2
The area of rectangle is 3xcm ^ 2 larger than that of trapezoid

The length of the rectangle is 2xcm, the width is 4cm, the length of the trapezoid is xcm, the length of the bottom is 3 times of the length of the top, and the height is 5cm? How much bigger?

Rectangle area: 2x × 4 = 8xcm2, trapezoid area: 0.5 × (x + 3x) × 5 = 10xcm2, ∵ length: 2xcm, ∵ 10x > 8x, ∵ trapezoid area: 2xcm2, ∵ 10x-8x = 2xcm2, ∵ 2xcm2