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Finding the Fourth Proportional to 100.38, 150.61 and 78.78

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Solution

The fourth proportional to 100.38, 150.61 and 78.78 is: 118.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.38 : 150.61 = 78.78 : x
  2. Step 2: Convert to fraction form
    100.38/150.61 = 78.78/x
  3. Step 3: Cross multiply
    100.38x = 150.61 × 78.78
  4. Step 4: Simplify right side
    100.38x = 11,864.86
  5. Step 5: Solve for x
    x = 11,864.86/100.38
  6. Step 6: Final answer
    x = 118.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.