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Finding the Fourth Proportional to 90.75, 125.25 and 64.92

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Solution

The fourth proportional to 90.75, 125.25 and 64.92 is: 89.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.75 : 125.25 = 64.92 : x
  2. Step 2: Convert to fraction form
    90.75/125.25 = 64.92/x
  3. Step 3: Cross multiply
    90.75x = 125.25 × 64.92
  4. Step 4: Simplify right side
    90.75x = 8,131.23
  5. Step 5: Solve for x
    x = 8,131.23/90.75
  6. Step 6: Final answer
    x = 89.60

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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.