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Finding the Fourth Proportional to 87.46, 120.66 and 56.40

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Solution

The fourth proportional to 87.46, 120.66 and 56.40 is: 77.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.46 : 120.66 = 56.40 : x
  2. Step 2: Convert to fraction form
    87.46/120.66 = 56.40/x
  3. Step 3: Cross multiply
    87.46x = 120.66 × 56.40
  4. Step 4: Simplify right side
    87.46x = 6,804.56
  5. Step 5: Solve for x
    x = 6,804.56/87.46
  6. Step 6: Final answer
    x = 77.80

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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.