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Finding the Fourth Proportional to 721.18, 1,080.69 and 432.30

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Solution

The fourth proportional to 721.18, 1,080.69 and 432.30 is: 647.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.18 : 1,080.69 = 432.30 : x
  2. Step 2: Convert to fraction form
    721.18/1,080.69 = 432.30/x
  3. Step 3: Cross multiply
    721.18x = 1,080.69 × 432.30
  4. Step 4: Simplify right side
    721.18x = 467,182.29
  5. Step 5: Solve for x
    x = 467,182.29/721.18
  6. Step 6: Final answer
    x = 647.80

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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.