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Finding the Fourth Proportional to 806.70, 1,209.80 and 513.78

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Solution

The fourth proportional to 806.70, 1,209.80 and 513.78 is: 770.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.70 : 1,209.80 = 513.78 : x
  2. Step 2: Convert to fraction form
    806.70/1,209.80 = 513.78/x
  3. Step 3: Cross multiply
    806.70x = 1,209.80 × 513.78
  4. Step 4: Simplify right side
    806.70x = 621,571.04
  5. Step 5: Solve for x
    x = 621,571.04/806.70
  6. Step 6: Final answer
    x = 770.51

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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.