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Finding the Fourth Proportional to 71.91, 99.28 and 55.57

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Solution

The fourth proportional to 71.91, 99.28 and 55.57 is: 76.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.91 : 99.28 = 55.57 : x
  2. Step 2: Convert to fraction form
    71.91/99.28 = 55.57/x
  3. Step 3: Cross multiply
    71.91x = 99.28 × 55.57
  4. Step 4: Simplify right side
    71.91x = 5,516.99
  5. Step 5: Solve for x
    x = 5,516.99/71.91
  6. Step 6: Final answer
    x = 76.72

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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.