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Finding the Fourth Proportional to 421.88, 581.67 and 311.31

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Solution

The fourth proportional to 421.88, 581.67 and 311.31 is: 429.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.88 : 581.67 = 311.31 : x
  2. Step 2: Convert to fraction form
    421.88/581.67 = 311.31/x
  3. Step 3: Cross multiply
    421.88x = 581.67 × 311.31
  4. Step 4: Simplify right side
    421.88x = 181,079.69
  5. Step 5: Solve for x
    x = 181,079.69/421.88
  6. Step 6: Final answer
    x = 429.23

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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.