The cross-sectional area of the reservoir dam is trapezoidal, angle B is equal to 30 degrees, angle c is equal to 45 degrees, and the dam crest ad = 6m, CD = 20m. Then, what are the length of the dam bottom BC and the cross-sectional area? (keep the integral part) [no figure]

Pass a and D as high AE and DF on bottom BC, and cross BC to e and F
Let DF be x meters, and in the triangular DFC, there are DF & # 178; + CF & # 178; = DC & # 178;,
That is, 2x & # 178; = 20 & # 178; X & # 178; = 400 △ 2x & # 178; = 200X = 10 √ 2
In the triangle Abe, ∵ B = 30 °, AE = DF = 10 √ 2,
∴AB＝2AE＝20√2BE²＝AB²－AE²＝(20√2)²－(10√2)²＝600BE＝10√6
Ψ BC = be + EF + FC = 10 √ 6 + 6 + 10 √ 2 ≈ 24.49 + 6 + 14.14 ≈ 44.6 (m)
Cross sectional area: (6 + 44.6) × 14.14 △ 2 ≈ 357.7 (M2)

The cross section of the reservoir dam is trapezoid, ∠ B = 30 ° and ∠ C = 45 ° and the dam crest ad = 6m and CD = 20m, then the length and cross section of BC at the dam bottom are as follows
It is the length and cross-sectional area of the dam bottom BC

The vertical lines are drawn from two points a and D to the dam bottom respectively. CD = 20m, ∠ C = 45 °, so the height of trapezoid is 20 divided by the root sign 2 (sorry, I won't type the root sign); and because ∠ B = 30 °, the final dam bottom length is 10 times the root sign 6 + 6 + 10 times the root sign 2. In this way (upper bottom + lower bottom) * height / 2 can be directly substituted into the formula~~

The cross section of a newly built channel is trapezoid (as shown in the figure). The area of this trapezoid is 432m2, the width of the channel bottom is 24m, and the width of the channel mouth is twice that of the channel bottom. How many meters is its depth?

432 × 2 ^ (24 + 24 × 2), = 864 ^ 72, = 12 (m), a: the canal depth is 12 M

A trapezoid is 16 meters at the top, 24 meters at the bottom and 30 meters high

Hello
Its area is (16 + 24) x30 △ 2 = 40x30 △ 2 = 600 square meters
What's its area (600 square meters)
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The area of a parallelogram is twice that of a trapezoid

Trapezoid area is 36 square meters, 3.6 meters at the bottom, 5.4 meters at the bottom, high X
Lie equation

Area of trapezoid = (upper bottom + lower bottom) × height △ 2
（3.6+5.4）x÷2=36
9x÷2=36
9x=36×2
9x=72
x=72÷9
x=8
Answer: the height of trapezoid is 8m

The area of a trapezoid is 36 square meters, and its height is 6 decimeters. The ratio of the top and bottom is 3:1. How many decimeters are the top and bottom?
To solve the problem in detail! ~ thank you~~

Top and bottom = 36 × 2 △ 6 = 12
12×3÷(3+1)=9
12×1÷(3+1)=3
A: the upper bottom is 9 decimeters and the lower bottom is 3 decimeters

The area of a trapezoid is 15 square centimeters, the upper bottom is 4.5 centimeters, the height is 3 centimeters, how many centimeters is the lower bottom

Let the base be x cm,
Area formula from trapezoid
Know 1 / 2 × (4.5 + x) × 3 = 15
That is 4.5 + x = 10
The solution is x = 5.5cm

The area of a trapezoid is 28 square centimeters, the upper bottom is 5 square centimeters, what is the lower bottom? Use the equation to solve
The area of a trapezoid is 28 square centimeters, the upper bottom is 5 square centimeters, and the height is 4 square centimeters. How much is the lower bottom? Solve by equation

Setting: the base is x cm
4（5+x）÷2=28
4（5+x）=28×2
20+4x=56
4x=36
x=9

[mathematical equation] the area of a trapezoid is 124 square centimeters. When it is 8 centimeters high, the upper bottom is 12 centimeters. How many centimeters is the lower bottom?
The area of a trapezoid is 124 square centimeters. When it is 8 centimeters high, the upper bottom is 12 centimeters. How many centimeters is the lower bottom? Please use the equation to solve it!

(12+x)*8/2=124
8*(12+x)=248
96+8x=248
8x=152
x=19
The bottom is 19 cm

The cross-sectional area of the reservoir dam is trapezoidal, angle B is equal to 30 degrees, angle c is equal to 45 degrees, and the dam crest ad = 6m, CD = 20m. Then, what are the length of the dam bottom BC and the cross-sectional area? (keep the integral part) [no figure]