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Finding the Fourth Proportional to 99.89, 149.68 and 78.17

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Solution

The fourth proportional to 99.89, 149.68 and 78.17 is: 117.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.89 : 149.68 = 78.17 : x
  2. Step 2: Convert to fraction form
    99.89/149.68 = 78.17/x
  3. Step 3: Cross multiply
    99.89x = 149.68 × 78.17
  4. Step 4: Simplify right side
    99.89x = 11,700.10
  5. Step 5: Solve for x
    x = 11,700.10/99.89
  6. Step 6: Final answer
    x = 117.13

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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.