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Finding the Fourth Proportional to 1,138.26, 1,570.79 and 640.90

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Solution

The fourth proportional to 1,138.26, 1,570.79 and 640.90 is: 884.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.26 : 1,570.79 = 640.90 : x
  2. Step 2: Convert to fraction form
    1,138.26/1,570.79 = 640.90/x
  3. Step 3: Cross multiply
    1,138.26x = 1,570.79 × 640.90
  4. Step 4: Simplify right side
    1,138.26x = 1,006,719.31
  5. Step 5: Solve for x
    x = 1,006,719.31/1,138.26
  6. Step 6: Final answer
    x = 884.44

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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.