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Finding the Fourth Proportional to 1,338.91, 2,009.19 and 645.65

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Solution

The fourth proportional to 1,338.91, 2,009.19 and 645.65 is: 968.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,338.91 : 2,009.19 = 645.65 : x
  2. Step 2: Convert to fraction form
    1,338.91/2,009.19 = 645.65/x
  3. Step 3: Cross multiply
    1,338.91x = 2,009.19 × 645.65
  4. Step 4: Simplify right side
    1,338.91x = 1,297,223.48
  5. Step 5: Solve for x
    x = 1,297,223.48/1,338.91
  6. Step 6: Final answer
    x = 968.87

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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.