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Finding the Fourth Proportional to 640.87, 961.30 and 424.40

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Solution

The fourth proportional to 640.87, 961.30 and 424.40 is: 636.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.87 : 961.30 = 424.40 : x
  2. Step 2: Convert to fraction form
    640.87/961.30 = 424.40/x
  3. Step 3: Cross multiply
    640.87x = 961.30 × 424.40
  4. Step 4: Simplify right side
    640.87x = 407,975.72
  5. Step 5: Solve for x
    x = 407,975.72/640.87
  6. Step 6: Final answer
    x = 636.60

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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.