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Finding the Fourth Proportional to 57.15, 78.82 and 40.78

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Solution

The fourth proportional to 57.15, 78.82 and 40.78 is: 56.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.15 : 78.82 = 40.78 : x
  2. Step 2: Convert to fraction form
    57.15/78.82 = 40.78/x
  3. Step 3: Cross multiply
    57.15x = 78.82 × 40.78
  4. Step 4: Simplify right side
    57.15x = 3,213.98
  5. Step 5: Solve for x
    x = 3,213.98/57.15
  6. Step 6: Final answer
    x = 56.24

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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.