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Finding the Fourth Proportional to 807.80, 1,212.30 and 647.42

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Solution

The fourth proportional to 807.80, 1,212.30 and 647.42 is: 971.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.80 : 1,212.30 = 647.42 : x
  2. Step 2: Convert to fraction form
    807.80/1,212.30 = 647.42/x
  3. Step 3: Cross multiply
    807.80x = 1,212.30 × 647.42
  4. Step 4: Simplify right side
    807.80x = 784,861.20
  5. Step 5: Solve for x
    x = 784,861.20/807.80
  6. Step 6: Final answer
    x = 971.61

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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.