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Finding the Fourth Proportional to 939.61, 1,399.48 and 890.20

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Solution

The fourth proportional to 939.61, 1,399.48 and 890.20 is: 1,325.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.61 : 1,399.48 = 890.20 : x
  2. Step 2: Convert to fraction form
    939.61/1,399.48 = 890.20/x
  3. Step 3: Cross multiply
    939.61x = 1,399.48 × 890.20
  4. Step 4: Simplify right side
    939.61x = 1,245,816.62
  5. Step 5: Solve for x
    x = 1,245,816.62/939.61
  6. Step 6: Final answer
    x = 1,325.89

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.