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Finding the Fourth Proportional to 721.68, 1,081.44 and 432.80

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Solution

The fourth proportional to 721.68, 1,081.44 and 432.80 is: 648.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.68 : 1,081.44 = 432.80 : x
  2. Step 2: Convert to fraction form
    721.68/1,081.44 = 432.80/x
  3. Step 3: Cross multiply
    721.68x = 1,081.44 × 432.80
  4. Step 4: Simplify right side
    721.68x = 468,047.23
  5. Step 5: Solve for x
    x = 468,047.23/721.68
  6. Step 6: Final answer
    x = 648.55

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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.