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Finding the Fourth Proportional to 811.59, 1,217.75 and 426.75

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Solution

The fourth proportional to 811.59, 1,217.75 and 426.75 is: 640.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.59 : 1,217.75 = 426.75 : x
  2. Step 2: Convert to fraction form
    811.59/1,217.75 = 426.75/x
  3. Step 3: Cross multiply
    811.59x = 1,217.75 × 426.75
  4. Step 4: Simplify right side
    811.59x = 519,672.68
  5. Step 5: Solve for x
    x = 519,672.68/811.59
  6. Step 6: Final answer
    x = 640.31

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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.