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Finding the Fourth Proportional to 63.23, 87.20 and 39.90

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Solution

The fourth proportional to 63.23, 87.20 and 39.90 is: 55.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.23 : 87.20 = 39.90 : x
  2. Step 2: Convert to fraction form
    63.23/87.20 = 39.90/x
  3. Step 3: Cross multiply
    63.23x = 87.20 × 39.90
  4. Step 4: Simplify right side
    63.23x = 3,479.08
  5. Step 5: Solve for x
    x = 3,479.08/63.23
  6. Step 6: Final answer
    x = 55.03

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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.