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Finding the Fourth Proportional to 809.18, 1,213.38 and 315.81

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Solution

The fourth proportional to 809.18, 1,213.38 and 315.81 is: 473.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.18 : 1,213.38 = 315.81 : x
  2. Step 2: Convert to fraction form
    809.18/1,213.38 = 315.81/x
  3. Step 3: Cross multiply
    809.18x = 1,213.38 × 315.81
  4. Step 4: Simplify right side
    809.18x = 383,197.54
  5. Step 5: Solve for x
    x = 383,197.54/809.18
  6. Step 6: Final answer
    x = 473.57

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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.