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Finding the Fourth Proportional to 87.20, 130.20 and 80.72

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Solution

The fourth proportional to 87.20, 130.20 and 80.72 is: 120.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.20 : 130.20 = 80.72 : x
  2. Step 2: Convert to fraction form
    87.20/130.20 = 80.72/x
  3. Step 3: Cross multiply
    87.20x = 130.20 × 80.72
  4. Step 4: Simplify right side
    87.20x = 10,509.34
  5. Step 5: Solve for x
    x = 10,509.34/87.20
  6. Step 6: Final answer
    x = 120.52

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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.