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Finding the Fourth Proportional to 811.29, 1,217.36 and 518.95

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Solution

The fourth proportional to 811.29, 1,217.36 and 518.95 is: 778.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.29 : 1,217.36 = 518.95 : x
  2. Step 2: Convert to fraction form
    811.29/1,217.36 = 518.95/x
  3. Step 3: Cross multiply
    811.29x = 1,217.36 × 518.95
  4. Step 4: Simplify right side
    811.29x = 631,751.79
  5. Step 5: Solve for x
    x = 631,751.79/811.29
  6. Step 6: Final answer
    x = 778.70

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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.