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Finding the Fourth Proportional to 57.20, 78.91 and 40.79

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Solution

The fourth proportional to 57.20, 78.91 and 40.79 is: 56.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.20 : 78.91 = 40.79 : x
  2. Step 2: Convert to fraction form
    57.20/78.91 = 40.79/x
  3. Step 3: Cross multiply
    57.20x = 78.91 × 40.79
  4. Step 4: Simplify right side
    57.20x = 3,218.74
  5. Step 5: Solve for x
    x = 3,218.74/57.20
  6. Step 6: Final answer
    x = 56.27

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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.