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Finding the Fourth Proportional to 77.70, 106.78 and 74.13

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Solution

The fourth proportional to 77.70, 106.78 and 74.13 is: 101.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.70 : 106.78 = 74.13 : x
  2. Step 2: Convert to fraction form
    77.70/106.78 = 74.13/x
  3. Step 3: Cross multiply
    77.70x = 106.78 × 74.13
  4. Step 4: Simplify right side
    77.70x = 7,915.60
  5. Step 5: Solve for x
    x = 7,915.60/77.70
  6. Step 6: Final answer
    x = 101.87

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.