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Finding the Fourth Proportional to 87.80, 121.10 and 52.81

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Solution

The fourth proportional to 87.80, 121.10 and 52.81 is: 72.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.80 : 121.10 = 52.81 : x
  2. Step 2: Convert to fraction form
    87.80/121.10 = 52.81/x
  3. Step 3: Cross multiply
    87.80x = 121.10 × 52.81
  4. Step 4: Simplify right side
    87.80x = 6,395.30
  5. Step 5: Solve for x
    x = 6,395.30/87.80
  6. Step 6: Final answer
    x = 72.84

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.