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Finding the Fourth Proportional to 78.11, 116.90 and 75.42

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Solution

The fourth proportional to 78.11, 116.90 and 75.42 is: 112.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.11 : 116.90 = 75.42 : x
  2. Step 2: Convert to fraction form
    78.11/116.90 = 75.42/x
  3. Step 3: Cross multiply
    78.11x = 116.90 × 75.42
  4. Step 4: Simplify right side
    78.11x = 8,816.22
  5. Step 5: Solve for x
    x = 8,816.22/78.11
  6. Step 6: Final answer
    x = 112.88

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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.