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Finding the Fourth Proportional to 71.95, 99.30 and 39.21

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Solution

The fourth proportional to 71.95, 99.30 and 39.21 is: 54.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.95 : 99.30 = 39.21 : x
  2. Step 2: Convert to fraction form
    71.95/99.30 = 39.21/x
  3. Step 3: Cross multiply
    71.95x = 99.30 × 39.21
  4. Step 4: Simplify right side
    71.95x = 3,892.86
  5. Step 5: Solve for x
    x = 3,892.86/71.95
  6. Step 6: Final answer
    x = 54.10

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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.