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Finding the Fourth Proportional to 78.78, 108.48 and 62.40

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Solution

The fourth proportional to 78.78, 108.48 and 62.40 is: 85.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.78 : 108.48 = 62.40 : x
  2. Step 2: Convert to fraction form
    78.78/108.48 = 62.40/x
  3. Step 3: Cross multiply
    78.78x = 108.48 × 62.40
  4. Step 4: Simplify right side
    78.78x = 6,769.15
  5. Step 5: Solve for x
    x = 6,769.15/78.78
  6. Step 6: Final answer
    x = 85.92

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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.