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Finding the Fourth Proportional to 2,780, 4,169.28 and 831.68

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Solution

The fourth proportional to 2,780, 4,169.28 and 831.68 is: 1,247.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,780 : 4,169.28 = 831.68 : x
  2. Step 2: Convert to fraction form
    2,780/4,169.28 = 831.68/x
  3. Step 3: Cross multiply
    2,780x = 4,169.28 × 831.68
  4. Step 4: Simplify right side
    2,780x = 3,467,506.79
  5. Step 5: Solve for x
    x = 3,467,506.79/2,780
  6. Step 6: Final answer
    x = 1,247.30

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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.