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Finding the Fourth Proportional to 99.78, 149.49 and 61.17

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Solution

The fourth proportional to 99.78, 149.49 and 61.17 is: 91.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.78 : 149.49 = 61.17 : x
  2. Step 2: Convert to fraction form
    99.78/149.49 = 61.17/x
  3. Step 3: Cross multiply
    99.78x = 149.49 × 61.17
  4. Step 4: Simplify right side
    99.78x = 9,144.30
  5. Step 5: Solve for x
    x = 9,144.30/99.78
  6. Step 6: Final answer
    x = 91.64

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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.