A trapezoid has an upper sole of 8 cm and a lower sole of 10 cm, with an area of 54 square cm. When the upper sole increases by 3 cm, the area increases by () square cm

A trapezoid has an upper sole of 8 cm and a lower sole of 10 cm, with an area of 54 square cm. When the upper sole increases by 3 cm, the area increases by () square cm

Height = 54 × 2 ÷ (10 + 8) = 6
Current area = (8 + 3 + 10) × 6 △ 2 = 63
Increased 63-54 = 9

The top of a trapezoid is 8 cm, the bottom is 12 cm, the area is 40 square cm, and the height is 10 cm______ ．

The height of trapezoid is 4cm, so the answer is 4cm

The length of a cuboid is 12 cm and the height is 8 cm. The area sum of the four sides of the blank part is 392 square cm. What is the area sum of the shadow part

Suppose the width is x cm,
12*X*2+8*X*2=392
X=392/40=9.8cm
Because there is no graph, I don't know which shadow part is, but it can be calculated according to the length, width and height~

The cuboid is 12 cm long and 8 cm high. The sum of the two sides of the shadow is 200 square cm
The two sides of the shadow are the left side and the bottom side. What's the volume of the cuboid?

Let the width be X
Left area = 8x
Bottom area = 12x
8X+12X=200
X = 10 cm
Cube volume = 12 * 10 * 8 = 960 CC