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Finding the Fourth Proportional to 99.80, 149.84 and 77.12

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Solution

The fourth proportional to 99.80, 149.84 and 77.12 is: 115.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.80 : 149.84 = 77.12 : x
  2. Step 2: Convert to fraction form
    99.80/149.84 = 77.12/x
  3. Step 3: Cross multiply
    99.80x = 149.84 × 77.12
  4. Step 4: Simplify right side
    99.80x = 11,555.28
  5. Step 5: Solve for x
    x = 11,555.28/99.80
  6. Step 6: Final answer
    x = 115.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.