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Finding the Fourth Proportional to 811.85, 1,217.78 and 672.65

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Solution

The fourth proportional to 811.85, 1,217.78 and 672.65 is: 1,008.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.85 : 1,217.78 = 672.65 : x
  2. Step 2: Convert to fraction form
    811.85/1,217.78 = 672.65/x
  3. Step 3: Cross multiply
    811.85x = 1,217.78 × 672.65
  4. Step 4: Simplify right side
    811.85x = 819,136.35
  5. Step 5: Solve for x
    x = 819,136.35/811.85
  6. Step 6: Final answer
    x = 1,008.98

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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.