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Finding the Fourth Proportional to 398.69, 549.38 and 305.43

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Solution

The fourth proportional to 398.69, 549.38 and 305.43 is: 420.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.69 : 549.38 = 305.43 : x
  2. Step 2: Convert to fraction form
    398.69/549.38 = 305.43/x
  3. Step 3: Cross multiply
    398.69x = 549.38 × 305.43
  4. Step 4: Simplify right side
    398.69x = 167,795.61
  5. Step 5: Solve for x
    x = 167,795.61/398.69
  6. Step 6: Final answer
    x = 420.87

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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.