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Finding the Fourth Proportional to 87.03, 129.98 and 77.31

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Solution

The fourth proportional to 87.03, 129.98 and 77.31 is: 115.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.03 : 129.98 = 77.31 : x
  2. Step 2: Convert to fraction form
    87.03/129.98 = 77.31/x
  3. Step 3: Cross multiply
    87.03x = 129.98 × 77.31
  4. Step 4: Simplify right side
    87.03x = 10,048.95
  5. Step 5: Solve for x
    x = 10,048.95/87.03
  6. Step 6: Final answer
    x = 115.47

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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.