Let’s solve this step by step.
We are given a proportion:
6 / 15 = x / 20
To solve for
x, we use cross-multiplication — that means multiplying the top of one fraction by the bottom of the other, and setting them equal.
So:
→ Multiply 6 (top left) by 20 (bottom right):
6 × 20 = 120
→ Multiply 15 (bottom left) by x (top right):
15 × x = 15x
Now set them equal:
15x = 120
Next, to find
x, divide both sides by 15:
x = 120 ÷ 15
Let’s calculate that:
15 goes into 120 how many times?
Well, 15 × 8 = 120 → so...
x = 8
✔ Double-check: Plug x = 8 back into the original proportion.
Left side: 6/15 = 0.4
Right side: 8/20 = 0.4
They match! So our answer is correct.
Final Answer:
8
Parent Tip: Review the logic above to help your child master the concept of geometry ratio and proportion worksheet.
