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Finding the Fourth Proportional to 693.79, 1,040.65 and 389.79

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Solution

The fourth proportional to 693.79, 1,040.65 and 389.79 is: 584.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    693.79 : 1,040.65 = 389.79 : x
  2. Step 2: Convert to fraction form
    693.79/1,040.65 = 389.79/x
  3. Step 3: Cross multiply
    693.79x = 1,040.65 × 389.79
  4. Step 4: Simplify right side
    693.79x = 405,633.01
  5. Step 5: Solve for x
    x = 405,633.01/693.79
  6. Step 6: Final answer
    x = 584.66

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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.