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Finding the Fourth Proportional to 100.70, 139.12 and 76.09

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Solution

The fourth proportional to 100.70, 139.12 and 76.09 is: 105.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.70 : 139.12 = 76.09 : x
  2. Step 2: Convert to fraction form
    100.70/139.12 = 76.09/x
  3. Step 3: Cross multiply
    100.70x = 139.12 × 76.09
  4. Step 4: Simplify right side
    100.70x = 10,585.83
  5. Step 5: Solve for x
    x = 10,585.83/100.70
  6. Step 6: Final answer
    x = 105.13

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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.