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Finding the Fourth Proportional to 398.12, 549.40 and 221.08

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Solution

The fourth proportional to 398.12, 549.40 and 221.08 is: 305.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.12 : 549.40 = 221.08 : x
  2. Step 2: Convert to fraction form
    398.12/549.40 = 221.08/x
  3. Step 3: Cross multiply
    398.12x = 549.40 × 221.08
  4. Step 4: Simplify right side
    398.12x = 121,461.35
  5. Step 5: Solve for x
    x = 121,461.35/398.12
  6. Step 6: Final answer
    x = 305.09

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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.