As A/c to formula=>(a+b+c)^2=a^2+b^2+c^2 +2(ab+bc+ca)=>20^2=90+2(ab+bc+ca)=>2(ab+bc+ca)=400-90=>ab+bc+ca=310/2=>ab+bc+ca=155.That's it...

Given Information:
a^2 b^2 c^2 = 90
a b c = 20

To Find:
ab bc ca

Solution:

Let's solve this problem step by step.

Step 1:
We are given the equation a^2 b^2 c^2 = 90. Since the product of squares is equal to 90, we can find the value of a^2 b^2 c^2 by taking the square root of both sides.

√(a^2 b^2 c^2) = √90

Simplifying this equation gives us:

abc = √90

Step 2:
We are also given the equation a b c = 20. From this equation, we can find the value of abc by multiplying all three variables together.

abc = 20

Step 3:
Now we have two equations with the variable abc:

abc = √90
abc = 20

Since both equations are equal to abc, we can set them equal to each other:

√90 = 20

Step 4:
To find the value of ab bc ca, we need to multiply the values of a, b, and c together.

ab bc ca = (abc) ^ 2

Since abc = 20, we can substitute this value into the equation:

ab bc ca = (20) ^ 2

Calculating this gives us:

ab bc ca = 400

Final Answer:
Therefore, the value of ab bc ca is 400.