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Finding the Fourth Proportional to 77.61, 115.71 and 71.70

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Solution

The fourth proportional to 77.61, 115.71 and 71.70 is: 106.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.61 : 115.71 = 71.70 : x
  2. Step 2: Convert to fraction form
    77.61/115.71 = 71.70/x
  3. Step 3: Cross multiply
    77.61x = 115.71 × 71.70
  4. Step 4: Simplify right side
    77.61x = 8,296.41
  5. Step 5: Solve for x
    x = 8,296.41/77.61
  6. Step 6: Final answer
    x = 106.90

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.