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Finding the Fourth Proportional to 721.21, 1,080.30 and 669.32

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Solution

The fourth proportional to 721.21, 1,080.30 and 669.32 is: 1,002.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.21 : 1,080.30 = 669.32 : x
  2. Step 2: Convert to fraction form
    721.21/1,080.30 = 669.32/x
  3. Step 3: Cross multiply
    721.21x = 1,080.30 × 669.32
  4. Step 4: Simplify right side
    721.21x = 723,064.85
  5. Step 5: Solve for x
    x = 723,064.85/721.21
  6. Step 6: Final answer
    x = 1,002.58

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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.