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Finding the Fourth Proportional to 421.74, 581.74 and 311.50

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Solution

The fourth proportional to 421.74, 581.74 and 311.50 is: 429.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.74 : 581.74 = 311.50 : x
  2. Step 2: Convert to fraction form
    421.74/581.74 = 311.50/x
  3. Step 3: Cross multiply
    421.74x = 581.74 × 311.50
  4. Step 4: Simplify right side
    421.74x = 181,212.01
  5. Step 5: Solve for x
    x = 181,212.01/421.74
  6. Step 6: Final answer
    x = 429.68

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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.