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Finding the Fourth Proportional to 39.90, 54.72 and 39.24

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Solution

The fourth proportional to 39.90, 54.72 and 39.24 is: 53.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.90 : 54.72 = 39.24 : x
  2. Step 2: Convert to fraction form
    39.90/54.72 = 39.24/x
  3. Step 3: Cross multiply
    39.90x = 54.72 × 39.24
  4. Step 4: Simplify right side
    39.90x = 2,147.21
  5. Step 5: Solve for x
    x = 2,147.21/39.90
  6. Step 6: Final answer
    x = 53.81

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.