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Finding the Fourth Proportional to 78.72, 108.36 and 57.96

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Solution

The fourth proportional to 78.72, 108.36 and 57.96 is: 79.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.72 : 108.36 = 57.96 : x
  2. Step 2: Convert to fraction form
    78.72/108.36 = 57.96/x
  3. Step 3: Cross multiply
    78.72x = 108.36 × 57.96
  4. Step 4: Simplify right side
    78.72x = 6,280.55
  5. Step 5: Solve for x
    x = 6,280.55/78.72
  6. Step 6: Final answer
    x = 79.78

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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.