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Finding the Fourth Proportional to 421.50, 581.50 and 311.24

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Solution

The fourth proportional to 421.50, 581.50 and 311.24 is: 429.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.50 : 581.50 = 311.24 : x
  2. Step 2: Convert to fraction form
    421.50/581.50 = 311.24/x
  3. Step 3: Cross multiply
    421.50x = 581.50 × 311.24
  4. Step 4: Simplify right side
    421.50x = 180,986.06
  5. Step 5: Solve for x
    x = 180,986.06/421.50
  6. Step 6: Final answer
    x = 429.39

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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.