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Finding the Fourth Proportional to 1,276.28, 1,912.86 and 728.72

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Solution

The fourth proportional to 1,276.28, 1,912.86 and 728.72 is: 1,092.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,276.28 : 1,912.86 = 728.72 : x
  2. Step 2: Convert to fraction form
    1,276.28/1,912.86 = 728.72/x
  3. Step 3: Cross multiply
    1,276.28x = 1,912.86 × 728.72
  4. Step 4: Simplify right side
    1,276.28x = 1,393,939.34
  5. Step 5: Solve for x
    x = 1,393,939.34/1,276.28
  6. Step 6: Final answer
    x = 1,092.19

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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.