The three squares have the same pressure on the ground, and the density is P1, P2, P3. P1 is greater than P2, and P3 is greater than P3

The three squares have the same pressure on the ground, and the density is P1, P2, P3. P1 is greater than P2, and P3 is greater than P3

∵F1=p1*s1=（ρ1gh1）*s1
F2=p2*s2=（ρ2gh2）*s2
F3 = P3 * S3 = (ρ 3gh3) * S3 (uniform object: liquid pressure formula can be converted to solid pressure formula)
And ∵ P1 = P2 = P3, ρ 1 ∵ ρ 2 ∵ ρ 3
Ψ H1 ＜ H2 ＜ H3 (H refers to edge length)
∴s1＜s2＜s3
∴F1＜F2＜F3
It may be wordy, but it's easier for LZ to understand
Or this:
∵p=ρgh,ρ1＞ρ2＞ρ3
{H1 ＜ H2 ＜ H3 (H is the side length)
∴S1＜S2＜S3
∴F1＜F2＜F3

The pressure of three solid cubes on the horizontal ground is the same, and their densities are P1, P2, P3 respectively. If P1 is greater than P2 and P3 is greater than P2, the pressure of cubes on the ground is the same
What is the pressure relationship? A F1 = F2 = 3 B F1 < F2 < F3 C F1 > F2 > F3 D cannot be determined

F = g = m × g = ρ × V × g = ρ × A & # 179; × g (a is the side length)
At the same time, f = P × s = P × A & # 178; ②
So ① = ②, that is p × A & # 178; = ρ × A & # 179; × G
So p = ρ × a × g, and because ρ 1 ＞ ρ 2 ＞ ρ 3, G remains unchanged, P1 = P2 = P3, so A1 ＜ A2 ＜ A3
So in 2, f = P × s = P × A & # 178; P is equal, A1 ﹤ A2 ﹤ A3,
So F1 < F2 < F3 choose B
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When the cube blocks a and B are placed on the horizontal table top, their pressure on the table top is equal, and the ratio of pressure is 9:4, what is the density ratio of a and B?
I think so
If f a: F B = 9:4, G A: G B = 9:4
M a: m b = 9:4
Because they have the same pressure on the table
So s a: S B = 4:9
Then V A: v b = 8:27
And because density is equal to mass divided by volume
So the density ratio of a and B is 9 / 8 to 4 / 27
But the answer is 2:3
I want to know what's wrong with my thinking
Why is it different from the standard answer

It's wrong here. According to the meaning of the title, G A / s a = G B / s B
S a / S B = G A / G B = 9:4 instead of 4:9
So V A / v b = 27:8 instead of 8:27