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Finding the Fourth Proportional to 87.70, 130.70 and 87.16

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Solution

The fourth proportional to 87.70, 130.70 and 87.16 is: 129.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.70 : 130.70 = 87.16 : x
  2. Step 2: Convert to fraction form
    87.70/130.70 = 87.16/x
  3. Step 3: Cross multiply
    87.70x = 130.70 × 87.16
  4. Step 4: Simplify right side
    87.70x = 11,391.81
  5. Step 5: Solve for x
    x = 11,391.81/87.70
  6. Step 6: Final answer
    x = 129.90

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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.