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Finding the Fourth Proportional to 969.98, 1,338.78 and 638.43

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Solution

The fourth proportional to 969.98, 1,338.78 and 638.43 is: 881.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.98 : 1,338.78 = 638.43 : x
  2. Step 2: Convert to fraction form
    969.98/1,338.78 = 638.43/x
  3. Step 3: Cross multiply
    969.98x = 1,338.78 × 638.43
  4. Step 4: Simplify right side
    969.98x = 854,718.63
  5. Step 5: Solve for x
    x = 854,718.63/969.98
  6. Step 6: Final answer
    x = 881.18

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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.