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Finding the Fourth Proportional to 721.16, 1,080.78 and 355.76

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Solution

The fourth proportional to 721.16, 1,080.78 and 355.76 is: 533.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.16 : 1,080.78 = 355.76 : x
  2. Step 2: Convert to fraction form
    721.16/1,080.78 = 355.76/x
  3. Step 3: Cross multiply
    721.16x = 1,080.78 × 355.76
  4. Step 4: Simplify right side
    721.16x = 384,498.29
  5. Step 5: Solve for x
    x = 384,498.29/721.16
  6. Step 6: Final answer
    x = 533.17

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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.