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Finding the Fourth Proportional to 691.56, 1,032.29 and 640.80

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Solution

The fourth proportional to 691.56, 1,032.29 and 640.80 is: 956.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.56 : 1,032.29 = 640.80 : x
  2. Step 2: Convert to fraction form
    691.56/1,032.29 = 640.80/x
  3. Step 3: Cross multiply
    691.56x = 1,032.29 × 640.80
  4. Step 4: Simplify right side
    691.56x = 661,491.43
  5. Step 5: Solve for x
    x = 661,491.43/691.56
  6. Step 6: Final answer
    x = 956.52

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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.