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Finding the Fourth Proportional to 807.91, 1,212.90 and 418.70

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Solution

The fourth proportional to 807.91, 1,212.90 and 418.70 is: 628.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.91 : 1,212.90 = 418.70 : x
  2. Step 2: Convert to fraction form
    807.91/1,212.90 = 418.70/x
  3. Step 3: Cross multiply
    807.91x = 1,212.90 × 418.70
  4. Step 4: Simplify right side
    807.91x = 507,844.26
  5. Step 5: Solve for x
    x = 507,844.26/807.91
  6. Step 6: Final answer
    x = 628.59

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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.