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Finding the Fourth Proportional to 76.68, 115.13 and 61.42

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Solution

The fourth proportional to 76.68, 115.13 and 61.42 is: 92.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.68 : 115.13 = 61.42 : x
  2. Step 2: Convert to fraction form
    76.68/115.13 = 61.42/x
  3. Step 3: Cross multiply
    76.68x = 115.13 × 61.42
  4. Step 4: Simplify right side
    76.68x = 7,071.15
  5. Step 5: Solve for x
    x = 7,071.15/76.68
  6. Step 6: Final answer
    x = 92.21

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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.