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Finding the Fourth Proportional to 99, 136.50 and 65.78

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Solution

The fourth proportional to 99, 136.50 and 65.78 is: 90.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    99 : 136.50 = 65.78 : x
  2. Step 2: Convert to fraction form
    99/136.50 = 65.78/x
  3. Step 3: Cross multiply
    99x = 136.50 × 65.78
  4. Step 4: Simplify right side
    99x = 8,978.97
  5. Step 5: Solve for x
    x = 8,978.97/99
  6. Step 6: Final answer
    x = 90.70

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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.