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Finding the Fourth Proportional to 398.38, 549.78 and 221.35

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Solution

The fourth proportional to 398.38, 549.78 and 221.35 is: 305.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.38 : 549.78 = 221.35 : x
  2. Step 2: Convert to fraction form
    398.38/549.78 = 221.35/x
  3. Step 3: Cross multiply
    398.38x = 549.78 × 221.35
  4. Step 4: Simplify right side
    398.38x = 121,692.70
  5. Step 5: Solve for x
    x = 121,692.70/398.38
  6. Step 6: Final answer
    x = 305.47

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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.