Home / 9.31-12.90-9

Finding the Fourth Proportional to 9.31, 12.90 and 9

Calculator

Solution

The fourth proportional to 9.31, 12.90 and 9 is: 12.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.31 : 12.90 = 9 : x
  2. Step 2: Convert to fraction form
    9.31/12.90 = 9/x
  3. Step 3: Cross multiply
    9.31x = 12.90 × 9
  4. Step 4: Simplify right side
    9.31x = 116.10
  5. Step 5: Solve for x
    x = 116.10/9.31
  6. Step 6: Final answer
    x = 12.47

Related Problems

Find fourth proportional to 4.66, 6.45 and 4.50
Half scale
Find fourth proportional to 18.62, 25.80 and 18
Double scale
Find fourth proportional to 10.31, 14.29 and 10
Similar ratio
Find fourth proportional to 13.97, 19.35 and 13.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.