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Finding the Fourth Proportional to 939.66, 1,297.31 and 641.26

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Solution

The fourth proportional to 939.66, 1,297.31 and 641.26 is: 885.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.66 : 1,297.31 = 641.26 : x
  2. Step 2: Convert to fraction form
    939.66/1,297.31 = 641.26/x
  3. Step 3: Cross multiply
    939.66x = 1,297.31 × 641.26
  4. Step 4: Simplify right side
    939.66x = 831,913.01
  5. Step 5: Solve for x
    x = 831,913.01/939.66
  6. Step 6: Final answer
    x = 885.33

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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.