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Finding the Fourth Proportional to 78.20, 107.90 and 49.08

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Solution

The fourth proportional to 78.20, 107.90 and 49.08 is: 67.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.20 : 107.90 = 49.08 : x
  2. Step 2: Convert to fraction form
    78.20/107.90 = 49.08/x
  3. Step 3: Cross multiply
    78.20x = 107.90 × 49.08
  4. Step 4: Simplify right side
    78.20x = 5,295.73
  5. Step 5: Solve for x
    x = 5,295.73/78.20
  6. Step 6: Final answer
    x = 67.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.