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Finding the Fourth Proportional to 1,138.40, 1,570.98 and 641

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Solution

The fourth proportional to 1,138.40, 1,570.98 and 641 is: 884.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.40 : 1,570.98 = 641 : x
  2. Step 2: Convert to fraction form
    1,138.40/1,570.98 = 641/x
  3. Step 3: Cross multiply
    1,138.40x = 1,570.98 × 641
  4. Step 4: Simplify right side
    1,138.40x = 1,006,998.18
  5. Step 5: Solve for x
    x = 1,006,998.18/1,138.40
  6. Step 6: Final answer
    x = 884.57

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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.