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Finding the Fourth Proportional to 722.40, 1,084.86 and 640.32

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Solution

The fourth proportional to 722.40, 1,084.86 and 640.32 is: 961.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    722.40 : 1,084.86 = 640.32 : x
  2. Step 2: Convert to fraction form
    722.40/1,084.86 = 640.32/x
  3. Step 3: Cross multiply
    722.40x = 1,084.86 × 640.32
  4. Step 4: Simplify right side
    722.40x = 694,657.56
  5. Step 5: Solve for x
    x = 694,657.56/722.40
  6. Step 6: Final answer
    x = 961.60

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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.