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Finding the Fourth Proportional to 398.96, 598.30 and 138.90

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Solution

The fourth proportional to 398.96, 598.30 and 138.90 is: 208.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.96 : 598.30 = 138.90 : x
  2. Step 2: Convert to fraction form
    398.96/598.30 = 138.90/x
  3. Step 3: Cross multiply
    398.96x = 598.30 × 138.90
  4. Step 4: Simplify right side
    398.96x = 83,101.02
  5. Step 5: Solve for x
    x = 83,101.02/398.96
  6. Step 6: Final answer
    x = 208.29

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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.