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Finding the Fourth Proportional to 99.75, 137.66 and 65.31

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Solution

The fourth proportional to 99.75, 137.66 and 65.31 is: 90.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.75 : 137.66 = 65.31 : x
  2. Step 2: Convert to fraction form
    99.75/137.66 = 65.31/x
  3. Step 3: Cross multiply
    99.75x = 137.66 × 65.31
  4. Step 4: Simplify right side
    99.75x = 8,990.25
  5. Step 5: Solve for x
    x = 8,990.25/99.75
  6. Step 6: Final answer
    x = 90.13

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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.