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Finding the Fourth Proportional to 1,286.80, 1,930.20 and 824.80

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Solution

The fourth proportional to 1,286.80, 1,930.20 and 824.80 is: 1,237.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.80 : 1,930.20 = 824.80 : x
  2. Step 2: Convert to fraction form
    1,286.80/1,930.20 = 824.80/x
  3. Step 3: Cross multiply
    1,286.80x = 1,930.20 × 824.80
  4. Step 4: Simplify right side
    1,286.80x = 1,592,028.96
  5. Step 5: Solve for x
    x = 1,592,028.96/1,286.80
  6. Step 6: Final answer
    x = 1,237.20

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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.