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Finding the Fourth Proportional to 809.70, 1,213.65 and 419.55

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Solution

The fourth proportional to 809.70, 1,213.65 and 419.55 is: 628.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.70 : 1,213.65 = 419.55 : x
  2. Step 2: Convert to fraction form
    809.70/1,213.65 = 419.55/x
  3. Step 3: Cross multiply
    809.70x = 1,213.65 × 419.55
  4. Step 4: Simplify right side
    809.70x = 509,186.86
  5. Step 5: Solve for x
    x = 509,186.86/809.70
  6. Step 6: Final answer
    x = 628.86

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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.