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Finding the Fourth Proportional to 78, 117 and 29.91

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Solution

The fourth proportional to 78, 117 and 29.91 is: 44.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 117 = 29.91 : x
  2. Step 2: Convert to fraction form
    78/117 = 29.91/x
  3. Step 3: Cross multiply
    78x = 117 × 29.91
  4. Step 4: Simplify right side
    78x = 3,499.47
  5. Step 5: Solve for x
    x = 3,499.47/78
  6. Step 6: Final answer
    x = 44.87

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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.