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Finding the Fourth Proportional to 77.13, 115.67 and 56.78

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Solution

The fourth proportional to 77.13, 115.67 and 56.78 is: 85.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.13 : 115.67 = 56.78 : x
  2. Step 2: Convert to fraction form
    77.13/115.67 = 56.78/x
  3. Step 3: Cross multiply
    77.13x = 115.67 × 56.78
  4. Step 4: Simplify right side
    77.13x = 6,567.74
  5. Step 5: Solve for x
    x = 6,567.74/77.13
  6. Step 6: Final answer
    x = 85.15

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.