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Finding the Fourth Proportional to 77.31, 106.70 and 56.66

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Solution

The fourth proportional to 77.31, 106.70 and 56.66 is: 78.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.31 : 106.70 = 56.66 : x
  2. Step 2: Convert to fraction form
    77.31/106.70 = 56.66/x
  3. Step 3: Cross multiply
    77.31x = 106.70 × 56.66
  4. Step 4: Simplify right side
    77.31x = 6,045.62
  5. Step 5: Solve for x
    x = 6,045.62/77.31
  6. Step 6: Final answer
    x = 78.20

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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.