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Finding the Fourth Proportional to 691.46, 1,037.49 and 639.21

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Solution

The fourth proportional to 691.46, 1,037.49 and 639.21 is: 959.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.46 : 1,037.49 = 639.21 : x
  2. Step 2: Convert to fraction form
    691.46/1,037.49 = 639.21/x
  3. Step 3: Cross multiply
    691.46x = 1,037.49 × 639.21
  4. Step 4: Simplify right side
    691.46x = 663,173.98
  5. Step 5: Solve for x
    x = 663,173.98/691.46
  6. Step 6: Final answer
    x = 959.09

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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.