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Finding the Fourth Proportional to 1,247.27, 1,721.31 and 687.86

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Solution

The fourth proportional to 1,247.27, 1,721.31 and 687.86 is: 949.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.27 : 1,721.31 = 687.86 : x
  2. Step 2: Convert to fraction form
    1,247.27/1,721.31 = 687.86/x
  3. Step 3: Cross multiply
    1,247.27x = 1,721.31 × 687.86
  4. Step 4: Simplify right side
    1,247.27x = 1,184,015.57
  5. Step 5: Solve for x
    x = 1,184,015.57/1,247.27
  6. Step 6: Final answer
    x = 949.29

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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.