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Finding the Fourth Proportional to 1,291, 1,781.52 and 731.40

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Solution

The fourth proportional to 1,291, 1,781.52 and 731.40 is: 1,009.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291 : 1,781.52 = 731.40 : x
  2. Step 2: Convert to fraction form
    1,291/1,781.52 = 731.40/x
  3. Step 3: Cross multiply
    1,291x = 1,781.52 × 731.40
  4. Step 4: Simplify right side
    1,291x = 1,303,003.73
  5. Step 5: Solve for x
    x = 1,303,003.73/1,291
  6. Step 6: Final answer
    x = 1,009.30

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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.