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Finding the Fourth Proportional to 91.91, 126.89 and 64.31

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Solution

The fourth proportional to 91.91, 126.89 and 64.31 is: 88.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.91 : 126.89 = 64.31 : x
  2. Step 2: Convert to fraction form
    91.91/126.89 = 64.31/x
  3. Step 3: Cross multiply
    91.91x = 126.89 × 64.31
  4. Step 4: Simplify right side
    91.91x = 8,159.34
  5. Step 5: Solve for x
    x = 8,159.34/91.91
  6. Step 6: Final answer
    x = 88.78

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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.