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Finding the Fourth Proportional to 87.61, 130.71 and 77.81

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Solution

The fourth proportional to 87.61, 130.71 and 77.81 is: 116.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.61 : 130.71 = 77.81 : x
  2. Step 2: Convert to fraction form
    87.61/130.71 = 77.81/x
  3. Step 3: Cross multiply
    87.61x = 130.71 × 77.81
  4. Step 4: Simplify right side
    87.61x = 10,170.92
  5. Step 5: Solve for x
    x = 10,170.92/87.61
  6. Step 6: Final answer
    x = 116.10

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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.