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Finding the Fourth Proportional to 76.78, 105.88 and 49.15

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Solution

The fourth proportional to 76.78, 105.88 and 49.15 is: 67.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.78 : 105.88 = 49.15 : x
  2. Step 2: Convert to fraction form
    76.78/105.88 = 49.15/x
  3. Step 3: Cross multiply
    76.78x = 105.88 × 49.15
  4. Step 4: Simplify right side
    76.78x = 5,203.76
  5. Step 5: Solve for x
    x = 5,203.76/76.78
  6. Step 6: Final answer
    x = 67.77

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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.