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Finding the Fourth Proportional to 809.40, 1,214.22 and 315.71

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Solution

The fourth proportional to 809.40, 1,214.22 and 315.71 is: 473.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.40 : 1,214.22 = 315.71 : x
  2. Step 2: Convert to fraction form
    809.40/1,214.22 = 315.71/x
  3. Step 3: Cross multiply
    809.40x = 1,214.22 × 315.71
  4. Step 4: Simplify right side
    809.40x = 383,339.82
  5. Step 5: Solve for x
    x = 383,339.82/809.40
  6. Step 6: Final answer
    x = 473.61

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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.