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Finding the Fourth Proportional to 56.20, 77.50 and 39.80

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Solution

The fourth proportional to 56.20, 77.50 and 39.80 is: 54.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.20 : 77.50 = 39.80 : x
  2. Step 2: Convert to fraction form
    56.20/77.50 = 39.80/x
  3. Step 3: Cross multiply
    56.20x = 77.50 × 39.80
  4. Step 4: Simplify right side
    56.20x = 3,084.50
  5. Step 5: Solve for x
    x = 3,084.50/56.20
  6. Step 6: Final answer
    x = 54.88

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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.