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Finding the Fourth Proportional to 717, 991.32 and 686.40

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Solution

The fourth proportional to 717, 991.32 and 686.40 is: 949.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    717 : 991.32 = 686.40 : x
  2. Step 2: Convert to fraction form
    717/991.32 = 686.40/x
  3. Step 3: Cross multiply
    717x = 991.32 × 686.40
  4. Step 4: Simplify right side
    717x = 680,442.05
  5. Step 5: Solve for x
    x = 680,442.05/717
  6. Step 6: Final answer
    x = 949.01

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.