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Finding the Fourth Proportional to 780.85, 1,077.78 and 449.31

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Solution

The fourth proportional to 780.85, 1,077.78 and 449.31 is: 620.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.85 : 1,077.78 = 449.31 : x
  2. Step 2: Convert to fraction form
    780.85/1,077.78 = 449.31/x
  3. Step 3: Cross multiply
    780.85x = 1,077.78 × 449.31
  4. Step 4: Simplify right side
    780.85x = 484,257.33
  5. Step 5: Solve for x
    x = 484,257.33/780.85
  6. Step 6: Final answer
    x = 620.17

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.