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Finding the Fourth Proportional to 1,289.52, 1,935 and 640.88

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Solution

The fourth proportional to 1,289.52, 1,935 and 640.88 is: 961.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.52 : 1,935 = 640.88 : x
  2. Step 2: Convert to fraction form
    1,289.52/1,935 = 640.88/x
  3. Step 3: Cross multiply
    1,289.52x = 1,935 × 640.88
  4. Step 4: Simplify right side
    1,289.52x = 1,240,102.80
  5. Step 5: Solve for x
    x = 1,240,102.80/1,289.52
  6. Step 6: Final answer
    x = 961.68

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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.