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Finding the Fourth Proportional to 997.82, 1,377.80 and 643.92

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Solution

The fourth proportional to 997.82, 1,377.80 and 643.92 is: 889.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.82 : 1,377.80 = 643.92 : x
  2. Step 2: Convert to fraction form
    997.82/1,377.80 = 643.92/x
  3. Step 3: Cross multiply
    997.82x = 1,377.80 × 643.92
  4. Step 4: Simplify right side
    997.82x = 887,192.98
  5. Step 5: Solve for x
    x = 887,192.98/997.82
  6. Step 6: Final answer
    x = 889.13

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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.