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Finding the Fourth Proportional to 721.26, 1,081.89 and 288.72

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Solution

The fourth proportional to 721.26, 1,081.89 and 288.72 is: 433.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.26 : 1,081.89 = 288.72 : x
  2. Step 2: Convert to fraction form
    721.26/1,081.89 = 288.72/x
  3. Step 3: Cross multiply
    721.26x = 1,081.89 × 288.72
  4. Step 4: Simplify right side
    721.26x = 312,363.28
  5. Step 5: Solve for x
    x = 312,363.28/721.26
  6. Step 6: Final answer
    x = 433.08

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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.