Simplify the ratio and calculate the ratio, 2:1/4 0.75/3 20﹪：0.6 Don't just write the answers

Simplify the ratio and calculate the ratio, 2:1/4 0.75/3 20﹪：0.6 Don't just write the answers

2:1/4=2×4=8:1=8
0.75/3=75/300=1:4=1/4
20﹪：0.6=2:6=1:3=1/3

Take a point O in △ ABC and connect Ao, Bo and CO to form three triangles, namely △ AOB, △ AOC and △ BOC, so that the area ratio of the three triangles is 3:5:7. Is point O unique?

It is proved that △ OAB, △ OAC. ∵ s △ OAB:S Let the extension line of AO and BC intersect at point D, then BD: DC = 3:5, that is, point D is a fixed point on BC, and O is on the straight line ad

How to change the inequality sign?

Let a > B
a-b>0
1/a-1/b=(b-a)/ab
b-a

A triangle and a parallelogram have the same base and height. The area of the triangle is known to be 12cm and the area of the parallelogram is () cm and 178;
60% off a piece of clothing, which is cheaper than the original price ()
A triangle and a parallelogram have the same base and height. The area of the triangle is known to be 12cm and the area of the parallelogram is () cm and 178;
Draw the largest circle in a square. The area of the circle is square. The area of the circle is ()
1 / A4 b78.5% C4 π D4
If the height of a cylinder remains unchanged and the radius of its bottom is reduced to 1 / 3 of the original, the volume will be reduced to 1 / 3 of the original
Calculation, can be simple, to be simple (recursive equation)
52 × 101 4.58-2.8-0.7 1 × 7 5 × 10 3
19 out of 20 (3 out of 4 + 1 out of 5) + 5 out of 4

Lower than the original price (40%)
The area of parallelogram is (24) CM & # 178;
The area of a circle is a square, and the area is (b 78.5%)
The volume is reduced to (1 / 9) of the original
52×101 = 52×(100+1) = 5200 + 52 = 5252
4.58-2.8-0.7 = 4.58 - 3.5 = 1.08
7×1/3×5/7×3/10 = (7×5/7)×(1/3×3/10) = 5×1/10 = 5/10 = 1/2
19/20÷（3/4 + 1/5）+ 5/4 = 19/20÷（15/20 + 4/20）+ 5/4 = 19/20÷（19/20）+ 5/4 = 1+5/4 = 9/4

Given the function f (x) = LG (1-x) + LG (1 + x) + the fourth power of x-2x # 178;
The range of function f (x) (- ∞, 0)

F (x) = LG (1-x & # 178;) + the fourth power of X - 2x & # 178;
∴x∈（-1,1）
f′（x）=（-2xlge）/（1-x²）+4x³-4x
Let f '(x) = 0, then x = 0
The maximum value is 0
When ∵ x →± 1, f (x) → - ∞
∴f（x）∈（- ∞,0】

The circumference of the cone's bottom surface is 12.56 cm and its height is 3 cm

The radius of the bottom is 2 cm, the area of the bottom is 12.56 square cm, and the volume is 12.56 cubic cm

Given that the sum of X and Y satisfying x + y = a, X-Y = 4A is 2, find the value of A
Wrong number. It should be x + 2Y = a

The solution of the equations is x = 5 / 2a, y = - 3 / 2a, so 5 / 2A + (- 3 / 2a) = 2
That is, a = 2

The bottom is 15 decimeters. The bottom is more than 1 decimeter higher than the half. Find the area of the quadrilateral

Height (15-1) △ 1 / 2 = 28 decimeters
Area 15 × 28 △ 2 = 210 square decimeters

All prime numbers are odd______ (judge right or wrong)

The smallest prime number (prime number) is 2, 2 is even, not odd, so all prime numbers are odd, which is wrong

A triangle warning sign, the bottom is 2.9 meters, the height is 1.5 meters. If you use paint, use 0.95 kg of paint per square meter, at least how many kg of paint should be prepared
No equation, no formula!

(2.9 * 1.5 / 2) * 0.95 = 2.06625 (kg)