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Finding the Fourth Proportional to 811.65, 1,217.15 and 349.20

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Solution

The fourth proportional to 811.65, 1,217.15 and 349.20 is: 523.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.65 : 1,217.15 = 349.20 : x
  2. Step 2: Convert to fraction form
    811.65/1,217.15 = 349.20/x
  3. Step 3: Cross multiply
    811.65x = 1,217.15 × 349.20
  4. Step 4: Simplify right side
    811.65x = 425,027.03
  5. Step 5: Solve for x
    x = 425,027.03/811.65
  6. Step 6: Final answer
    x = 523.66

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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.