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Finding the Fourth Proportional to 1,371.21, 2,057.12 and 640.38

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Solution

The fourth proportional to 1,371.21, 2,057.12 and 640.38 is: 960.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,371.21 : 2,057.12 = 640.38 : x
  2. Step 2: Convert to fraction form
    1,371.21/2,057.12 = 640.38/x
  3. Step 3: Cross multiply
    1,371.21x = 2,057.12 × 640.38
  4. Step 4: Simplify right side
    1,371.21x = 1,317,345.42
  5. Step 5: Solve for x
    x = 1,317,345.42/1,371.21
  6. Step 6: Final answer
    x = 960.72

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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.