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Finding the Fourth Proportional to 1,380.89, 2,071.07 and 640.47

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Solution

The fourth proportional to 1,380.89, 2,071.07 and 640.47 is: 960.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.89 : 2,071.07 = 640.47 : x
  2. Step 2: Convert to fraction form
    1,380.89/2,071.07 = 640.47/x
  3. Step 3: Cross multiply
    1,380.89x = 2,071.07 × 640.47
  4. Step 4: Simplify right side
    1,380.89x = 1,326,458.20
  5. Step 5: Solve for x
    x = 1,326,458.20/1,380.89
  6. Step 6: Final answer
    x = 960.58

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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.