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Finding the Fourth Proportional to 398.70, 550.23 and 221.67

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Solution

The fourth proportional to 398.70, 550.23 and 221.67 is: 305.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.70 : 550.23 = 221.67 : x
  2. Step 2: Convert to fraction form
    398.70/550.23 = 221.67/x
  3. Step 3: Cross multiply
    398.70x = 550.23 × 221.67
  4. Step 4: Simplify right side
    398.70x = 121,970.72
  5. Step 5: Solve for x
    x = 121,970.72/398.70
  6. Step 6: Final answer
    x = 305.92

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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.