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Finding the Fourth Proportional to 721.48, 1,079.64 and 679.90

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Solution

The fourth proportional to 721.48, 1,079.64 and 679.90 is: 1,017.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.48 : 1,079.64 = 679.90 : x
  2. Step 2: Convert to fraction form
    721.48/1,079.64 = 679.90/x
  3. Step 3: Cross multiply
    721.48x = 1,079.64 × 679.90
  4. Step 4: Simplify right side
    721.48x = 734,047.24
  5. Step 5: Solve for x
    x = 734,047.24/721.48
  6. Step 6: Final answer
    x = 1,017.42

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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.