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Finding the Fourth Proportional to 398.68, 598.18 and 142.20

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Solution

The fourth proportional to 398.68, 598.18 and 142.20 is: 213.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.68 : 598.18 = 142.20 : x
  2. Step 2: Convert to fraction form
    398.68/598.18 = 142.20/x
  3. Step 3: Cross multiply
    398.68x = 598.18 × 142.20
  4. Step 4: Simplify right side
    398.68x = 85,061.20
  5. Step 5: Solve for x
    x = 85,061.20/398.68
  6. Step 6: Final answer
    x = 213.36

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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.