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Finding the Fourth Proportional to 398.79, 550.40 and 305.33

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Solution

The fourth proportional to 398.79, 550.40 and 305.33 is: 421.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.79 : 550.40 = 305.33 : x
  2. Step 2: Convert to fraction form
    398.79/550.40 = 305.33/x
  3. Step 3: Cross multiply
    398.79x = 550.40 × 305.33
  4. Step 4: Simplify right side
    398.79x = 168,049.35
  5. Step 5: Solve for x
    x = 168,049.35/398.79
  6. Step 6: Final answer
    x = 421.40

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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.