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Finding the Fourth Proportional to 721.14, 1,081.78 and 355.58

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Solution

The fourth proportional to 721.14, 1,081.78 and 355.58 is: 533.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.14 : 1,081.78 = 355.58 : x
  2. Step 2: Convert to fraction form
    721.14/1,081.78 = 355.58/x
  3. Step 3: Cross multiply
    721.14x = 1,081.78 × 355.58
  4. Step 4: Simplify right side
    721.14x = 384,655.03
  5. Step 5: Solve for x
    x = 384,655.03/721.14
  6. Step 6: Final answer
    x = 533.40

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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.