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Finding the Fourth Proportional to 721.20, 1,080.72 and 395.58

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Solution

The fourth proportional to 721.20, 1,080.72 and 395.58 is: 592.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.20 : 1,080.72 = 395.58 : x
  2. Step 2: Convert to fraction form
    721.20/1,080.72 = 395.58/x
  3. Step 3: Cross multiply
    721.20x = 1,080.72 × 395.58
  4. Step 4: Simplify right side
    721.20x = 427,511.22
  5. Step 5: Solve for x
    x = 427,511.22/721.20
  6. Step 6: Final answer
    x = 592.78

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1.5x scale

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.