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Finding the Fourth Proportional to 394.40, 543.38 and 311.48

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Solution

The fourth proportional to 394.40, 543.38 and 311.48 is: 429.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    394.40 : 543.38 = 311.48 : x
  2. Step 2: Convert to fraction form
    394.40/543.38 = 311.48/x
  3. Step 3: Cross multiply
    394.40x = 543.38 × 311.48
  4. Step 4: Simplify right side
    394.40x = 169,247.73
  5. Step 5: Solve for x
    x = 169,247.73/394.40
  6. Step 6: Final answer
    x = 429.13

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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.