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Finding the Fourth Proportional to 811.85, 1,217.36 and 263.68

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Solution

The fourth proportional to 811.85, 1,217.36 and 263.68 is: 395.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.85 : 1,217.36 = 263.68 : x
  2. Step 2: Convert to fraction form
    811.85/1,217.36 = 263.68/x
  3. Step 3: Cross multiply
    811.85x = 1,217.36 × 263.68
  4. Step 4: Simplify right side
    811.85x = 320,991.10
  5. Step 5: Solve for x
    x = 320,991.10/811.85
  6. Step 6: Final answer
    x = 395.38

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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.