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Finding the Fourth Proportional to 1,961.40, 2,939.98 and 728.79

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Solution

The fourth proportional to 1,961.40, 2,939.98 and 728.79 is: 1,092.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,961.40 : 2,939.98 = 728.79 : x
  2. Step 2: Convert to fraction form
    1,961.40/2,939.98 = 728.79/x
  3. Step 3: Cross multiply
    1,961.40x = 2,939.98 × 728.79
  4. Step 4: Simplify right side
    1,961.40x = 2,142,628.02
  5. Step 5: Solve for x
    x = 2,142,628.02/1,961.40
  6. Step 6: Final answer
    x = 1,092.40

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.