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Finding the Fourth Proportional to 398.42, 549.82 and 221.40

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Solution

The fourth proportional to 398.42, 549.82 and 221.40 is: 305.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.42 : 549.82 = 221.40 : x
  2. Step 2: Convert to fraction form
    398.42/549.82 = 221.40/x
  3. Step 3: Cross multiply
    398.42x = 549.82 × 221.40
  4. Step 4: Simplify right side
    398.42x = 121,730.42
  5. Step 5: Solve for x
    x = 121,730.42/398.42
  6. Step 6: Final answer
    x = 305.53

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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.