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Finding the Fourth Proportional to 809.50, 1,214.20 and 261.70

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Solution

The fourth proportional to 809.50, 1,214.20 and 261.70 is: 392.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.50 : 1,214.20 = 261.70 : x
  2. Step 2: Convert to fraction form
    809.50/1,214.20 = 261.70/x
  3. Step 3: Cross multiply
    809.50x = 1,214.20 × 261.70
  4. Step 4: Simplify right side
    809.50x = 317,756.14
  5. Step 5: Solve for x
    x = 317,756.14/809.50
  6. Step 6: Final answer
    x = 392.53

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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.