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Finding the Fourth Proportional to 398.50, 549.89 and 221.47

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Solution

The fourth proportional to 398.50, 549.89 and 221.47 is: 305.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.50 : 549.89 = 221.47 : x
  2. Step 2: Convert to fraction form
    398.50/549.89 = 221.47/x
  3. Step 3: Cross multiply
    398.50x = 549.89 × 221.47
  4. Step 4: Simplify right side
    398.50x = 121,782.49
  5. Step 5: Solve for x
    x = 121,782.49/398.50
  6. Step 6: Final answer
    x = 305.60

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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.