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Finding the Fourth Proportional to 1,138.13, 1,570.62 and 640.79

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Solution

The fourth proportional to 1,138.13, 1,570.62 and 640.79 is: 884.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.13 : 1,570.62 = 640.79 : x
  2. Step 2: Convert to fraction form
    1,138.13/1,570.62 = 640.79/x
  3. Step 3: Cross multiply
    1,138.13x = 1,570.62 × 640.79
  4. Step 4: Simplify right side
    1,138.13x = 1,006,437.59
  5. Step 5: Solve for x
    x = 1,006,437.59/1,138.13
  6. Step 6: Final answer
    x = 884.29

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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.