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Finding the Fourth Proportional to 691.35, 1,031.61 and 687.30

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Solution

The fourth proportional to 691.35, 1,031.61 and 687.30 is: 1,025.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.35 : 1,031.61 = 687.30 : x
  2. Step 2: Convert to fraction form
    691.35/1,031.61 = 687.30/x
  3. Step 3: Cross multiply
    691.35x = 1,031.61 × 687.30
  4. Step 4: Simplify right side
    691.35x = 709,025.55
  5. Step 5: Solve for x
    x = 709,025.55/691.35
  6. Step 6: Final answer
    x = 1,025.57

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.