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Finding the Fourth Proportional to 91.91, 126.98 and 78.24

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Solution

The fourth proportional to 91.91, 126.98 and 78.24 is: 108.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.91 : 126.98 = 78.24 : x
  2. Step 2: Convert to fraction form
    91.91/126.98 = 78.24/x
  3. Step 3: Cross multiply
    91.91x = 126.98 × 78.24
  4. Step 4: Simplify right side
    91.91x = 9,934.92
  5. Step 5: Solve for x
    x = 9,934.92/91.91
  6. Step 6: Final answer
    x = 108.09

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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.