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Finding the Third Proportional to 643.03 and 991.31

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Solution

The third proportional to 643.03 and 991.31 is: 1,528.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.03 : 991.31 = 991.31 : x
  2. Step 2: Convert to fraction form
    643.03/991.31 = 991.31/x
  3. Step 3: Cross multiply
    643.03x = 991.31 × 991.31
  4. Step 4: Simplify right side
    643.03x = 982,700.47
  5. Step 5: Solve for x
    x = 982,700.47/643.03
  6. Step 6: Final answer
    x = 1,528.23

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Why These Related Problems?

These problems maintain the same ratio (1.54) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.