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Finding the Fourth Proportional to 113.90, 157.11 and 78.87

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Solution

The fourth proportional to 113.90, 157.11 and 78.87 is: 108.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.90 : 157.11 = 78.87 : x
  2. Step 2: Convert to fraction form
    113.90/157.11 = 78.87/x
  3. Step 3: Cross multiply
    113.90x = 157.11 × 78.87
  4. Step 4: Simplify right side
    113.90x = 12,391.27
  5. Step 5: Solve for x
    x = 12,391.27/113.90
  6. Step 6: Final answer
    x = 108.79

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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.