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Finding the Fourth Proportional to 1,138.05, 1,570.66 and 640.79

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Solution

The fourth proportional to 1,138.05, 1,570.66 and 640.79 is: 884.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.05 : 1,570.66 = 640.79 : x
  2. Step 2: Convert to fraction form
    1,138.05/1,570.66 = 640.79/x
  3. Step 3: Cross multiply
    1,138.05x = 1,570.66 × 640.79
  4. Step 4: Simplify right side
    1,138.05x = 1,006,453.77
  5. Step 5: Solve for x
    x = 1,006,453.77/1,138.05
  6. Step 6: Final answer
    x = 884.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.