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Finding the Fourth Proportional to 809.30, 1,213.90 and 315.86

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Solution

The fourth proportional to 809.30, 1,213.90 and 315.86 is: 473.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.30 : 1,213.90 = 315.86 : x
  2. Step 2: Convert to fraction form
    809.30/1,213.90 = 315.86/x
  3. Step 3: Cross multiply
    809.30x = 1,213.90 × 315.86
  4. Step 4: Simplify right side
    809.30x = 383,424.57
  5. Step 5: Solve for x
    x = 383,424.57/809.30
  6. Step 6: Final answer
    x = 473.77

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.