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Finding the Fourth Proportional to 56.71, 78.19 and 39.20

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Solution

The fourth proportional to 56.71, 78.19 and 39.20 is: 54.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.71 : 78.19 = 39.20 : x
  2. Step 2: Convert to fraction form
    56.71/78.19 = 39.20/x
  3. Step 3: Cross multiply
    56.71x = 78.19 × 39.20
  4. Step 4: Simplify right side
    56.71x = 3,064.56
  5. Step 5: Solve for x
    x = 3,064.56/56.71
  6. Step 6: Final answer
    x = 54.04

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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.