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Finding the Fourth Proportional to 1,379.30, 2,069.45 and 639.26

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Solution

The fourth proportional to 1,379.30, 2,069.45 and 639.26 is: 959.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.30 : 2,069.45 = 639.26 : x
  2. Step 2: Convert to fraction form
    1,379.30/2,069.45 = 639.26/x
  3. Step 3: Cross multiply
    1,379.30x = 2,069.45 × 639.26
  4. Step 4: Simplify right side
    1,379.30x = 1,322,915.62
  5. Step 5: Solve for x
    x = 1,322,915.62/1,379.30
  6. Step 6: Final answer
    x = 959.12

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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.