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Finding the Fourth Proportional to 91.78, 126.57 and 65.86

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Solution

The fourth proportional to 91.78, 126.57 and 65.86 is: 90.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.78 : 126.57 = 65.86 : x
  2. Step 2: Convert to fraction form
    91.78/126.57 = 65.86/x
  3. Step 3: Cross multiply
    91.78x = 126.57 × 65.86
  4. Step 4: Simplify right side
    91.78x = 8,335.90
  5. Step 5: Solve for x
    x = 8,335.90/91.78
  6. Step 6: Final answer
    x = 90.82

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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.