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Finding the Fourth Proportional to 71.70, 99.47 and 65.22

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Solution

The fourth proportional to 71.70, 99.47 and 65.22 is: 90.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.70 : 99.47 = 65.22 : x
  2. Step 2: Convert to fraction form
    71.70/99.47 = 65.22/x
  3. Step 3: Cross multiply
    71.70x = 99.47 × 65.22
  4. Step 4: Simplify right side
    71.70x = 6,487.11
  5. Step 5: Solve for x
    x = 6,487.11/71.70
  6. Step 6: Final answer
    x = 90.48

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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.