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Finding the Fourth Proportional to 55.80, 76.87 and 39.40

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Solution

The fourth proportional to 55.80, 76.87 and 39.40 is: 54.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.80 : 76.87 = 39.40 : x
  2. Step 2: Convert to fraction form
    55.80/76.87 = 39.40/x
  3. Step 3: Cross multiply
    55.80x = 76.87 × 39.40
  4. Step 4: Simplify right side
    55.80x = 3,028.68
  5. Step 5: Solve for x
    x = 3,028.68/55.80
  6. Step 6: Final answer
    x = 54.28

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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.