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Finding the Fourth Proportional to 31.13, 42.95 and 18.20

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Solution

The fourth proportional to 31.13, 42.95 and 18.20 is: 25.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.13 : 42.95 = 18.20 : x
  2. Step 2: Convert to fraction form
    31.13/42.95 = 18.20/x
  3. Step 3: Cross multiply
    31.13x = 42.95 × 18.20
  4. Step 4: Simplify right side
    31.13x = 781.52
  5. Step 5: Solve for x
    x = 781.52/31.13
  6. Step 6: Final answer
    x = 25.11

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.