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Finding the Fourth Proportional to 780.50, 1,169.09 and 505.78

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Solution

The fourth proportional to 780.50, 1,169.09 and 505.78 is: 757.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.50 : 1,169.09 = 505.78 : x
  2. Step 2: Convert to fraction form
    780.50/1,169.09 = 505.78/x
  3. Step 3: Cross multiply
    780.50x = 1,169.09 × 505.78
  4. Step 4: Simplify right side
    780.50x = 591,293.97
  5. Step 5: Solve for x
    x = 591,293.97/780.50
  6. Step 6: Final answer
    x = 757.58

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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.