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Finding the Fourth Proportional to 99.65, 137.54 and 62.78

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Solution

The fourth proportional to 99.65, 137.54 and 62.78 is: 86.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.65 : 137.54 = 62.78 : x
  2. Step 2: Convert to fraction form
    99.65/137.54 = 62.78/x
  3. Step 3: Cross multiply
    99.65x = 137.54 × 62.78
  4. Step 4: Simplify right side
    99.65x = 8,635.26
  5. Step 5: Solve for x
    x = 8,635.26/99.65
  6. Step 6: Final answer
    x = 86.66

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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.