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Finding the Fourth Proportional to 679.20, 1,017 and 643.44

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Solution

The fourth proportional to 679.20, 1,017 and 643.44 is: 963.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.20 : 1,017 = 643.44 : x
  2. Step 2: Convert to fraction form
    679.20/1,017 = 643.44/x
  3. Step 3: Cross multiply
    679.20x = 1,017 × 643.44
  4. Step 4: Simplify right side
    679.20x = 654,378.48
  5. Step 5: Solve for x
    x = 654,378.48/679.20
  6. Step 6: Final answer
    x = 963.45

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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.