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Finding the Fourth Proportional to 57.81, 79.76 and 39.42

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Solution

The fourth proportional to 57.81, 79.76 and 39.42 is: 54.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.81 : 79.76 = 39.42 : x
  2. Step 2: Convert to fraction form
    57.81/79.76 = 39.42/x
  3. Step 3: Cross multiply
    57.81x = 79.76 × 39.42
  4. Step 4: Simplify right side
    57.81x = 3,144.24
  5. Step 5: Solve for x
    x = 3,144.24/57.81
  6. Step 6: Final answer
    x = 54.39

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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.