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Finding the Fourth Proportional to 811.43, 1,217.28 and 317.79

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Solution

The fourth proportional to 811.43, 1,217.28 and 317.79 is: 476.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.43 : 1,217.28 = 317.79 : x
  2. Step 2: Convert to fraction form
    811.43/1,217.28 = 317.79/x
  3. Step 3: Cross multiply
    811.43x = 1,217.28 × 317.79
  4. Step 4: Simplify right side
    811.43x = 386,838.82
  5. Step 5: Solve for x
    x = 386,838.82/811.43
  6. Step 6: Final answer
    x = 476.73

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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.