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Finding the Fourth Proportional to 100.71, 139.13 and 77.49

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Solution

The fourth proportional to 100.71, 139.13 and 77.49 is: 107.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.71 : 139.13 = 77.49 : x
  2. Step 2: Convert to fraction form
    100.71/139.13 = 77.49/x
  3. Step 3: Cross multiply
    100.71x = 139.13 × 77.49
  4. Step 4: Simplify right side
    100.71x = 10,781.52
  5. Step 5: Solve for x
    x = 10,781.52/100.71
  6. Step 6: Final answer
    x = 107.06

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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.