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Finding the Fourth Proportional to 87.76, 121.11 and 64.43

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Solution

The fourth proportional to 87.76, 121.11 and 64.43 is: 88.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.76 : 121.11 = 64.43 : x
  2. Step 2: Convert to fraction form
    87.76/121.11 = 64.43/x
  3. Step 3: Cross multiply
    87.76x = 121.11 × 64.43
  4. Step 4: Simplify right side
    87.76x = 7,803.42
  5. Step 5: Solve for x
    x = 7,803.42/87.76
  6. Step 6: Final answer
    x = 88.92

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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.