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Finding the Fourth Proportional to 324.90, 487.20 and 142.20

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Solution

The fourth proportional to 324.90, 487.20 and 142.20 is: 213.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    324.90 : 487.20 = 142.20 : x
  2. Step 2: Convert to fraction form
    324.90/487.20 = 142.20/x
  3. Step 3: Cross multiply
    324.90x = 487.20 × 142.20
  4. Step 4: Simplify right side
    324.90x = 69,279.84
  5. Step 5: Solve for x
    x = 69,279.84/324.90
  6. Step 6: Final answer
    x = 213.23

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.