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Finding the Fourth Proportional to 99.72, 148.85 and 87.57

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Solution

The fourth proportional to 99.72, 148.85 and 87.57 is: 130.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.72 : 148.85 = 87.57 : x
  2. Step 2: Convert to fraction form
    99.72/148.85 = 87.57/x
  3. Step 3: Cross multiply
    99.72x = 148.85 × 87.57
  4. Step 4: Simplify right side
    99.72x = 13,033.61
  5. Step 5: Solve for x
    x = 13,033.61/99.72
  6. Step 6: Final answer
    x = 130.71

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.