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Finding the Fourth Proportional to 101.32, 139.70 and 76.80

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Solution

The fourth proportional to 101.32, 139.70 and 76.80 is: 105.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.32 : 139.70 = 76.80 : x
  2. Step 2: Convert to fraction form
    101.32/139.70 = 76.80/x
  3. Step 3: Cross multiply
    101.32x = 139.70 × 76.80
  4. Step 4: Simplify right side
    101.32x = 10,728.96
  5. Step 5: Solve for x
    x = 10,728.96/101.32
  6. Step 6: Final answer
    x = 105.89

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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.