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Finding the Fourth Proportional to 1,338.71, 2,008.67 and 689.90

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Solution

The fourth proportional to 1,338.71, 2,008.67 and 689.90 is: 1,035.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,338.71 : 2,008.67 = 689.90 : x
  2. Step 2: Convert to fraction form
    1,338.71/2,008.67 = 689.90/x
  3. Step 3: Cross multiply
    1,338.71x = 2,008.67 × 689.90
  4. Step 4: Simplify right side
    1,338.71x = 1,385,767.94
  5. Step 5: Solve for x
    x = 1,385,767.94/1,338.71
  6. Step 6: Final answer
    x = 1,035.16

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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.