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Finding the Fourth Proportional to 71.85, 99.15 and 39.10

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Solution

The fourth proportional to 71.85, 99.15 and 39.10 is: 53.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.85 : 99.15 = 39.10 : x
  2. Step 2: Convert to fraction form
    71.85/99.15 = 39.10/x
  3. Step 3: Cross multiply
    71.85x = 99.15 × 39.10
  4. Step 4: Simplify right side
    71.85x = 3,876.67
  5. Step 5: Solve for x
    x = 3,876.67/71.85
  6. Step 6: Final answer
    x = 53.96

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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.