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Finding the Fourth Proportional to 829.07, 1,242.64 and 389.78

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Solution

The fourth proportional to 829.07, 1,242.64 and 389.78 is: 584.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    829.07 : 1,242.64 = 389.78 : x
  2. Step 2: Convert to fraction form
    829.07/1,242.64 = 389.78/x
  3. Step 3: Cross multiply
    829.07x = 1,242.64 × 389.78
  4. Step 4: Simplify right side
    829.07x = 484,355.15
  5. Step 5: Solve for x
    x = 484,355.15/829.07
  6. Step 6: Final answer
    x = 584.22

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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.