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Finding the Fourth Proportional to 421.75, 581.85 and 311.49

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Solution

The fourth proportional to 421.75, 581.85 and 311.49 is: 429.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.75 : 581.85 = 311.49 : x
  2. Step 2: Convert to fraction form
    421.75/581.85 = 311.49/x
  3. Step 3: Cross multiply
    421.75x = 581.85 × 311.49
  4. Step 4: Simplify right side
    421.75x = 181,240.46
  5. Step 5: Solve for x
    x = 181,240.46/421.75
  6. Step 6: Final answer
    x = 429.73

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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.