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Finding the Fourth Proportional to 829.20, 1,242.45 and 780.60

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Solution

The fourth proportional to 829.20, 1,242.45 and 780.60 is: 1,169.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    829.20 : 1,242.45 = 780.60 : x
  2. Step 2: Convert to fraction form
    829.20/1,242.45 = 780.60/x
  3. Step 3: Cross multiply
    829.20x = 1,242.45 × 780.60
  4. Step 4: Simplify right side
    829.20x = 969,856.47
  5. Step 5: Solve for x
    x = 969,856.47/829.20
  6. Step 6: Final answer
    x = 1,169.63

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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.