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Finding the Fourth Proportional to 57.79, 79.78 and 39.47

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Solution

The fourth proportional to 57.79, 79.78 and 39.47 is: 54.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.79 : 79.78 = 39.47 : x
  2. Step 2: Convert to fraction form
    57.79/79.78 = 39.47/x
  3. Step 3: Cross multiply
    57.79x = 79.78 × 39.47
  4. Step 4: Simplify right side
    57.79x = 3,148.92
  5. Step 5: Solve for x
    x = 3,148.92/57.79
  6. Step 6: Final answer
    x = 54.49

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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.