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Finding the Fourth Proportional to 1,247.22, 1,721.14 and 687.71

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Solution

The fourth proportional to 1,247.22, 1,721.14 and 687.71 is: 949.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.22 : 1,721.14 = 687.71 : x
  2. Step 2: Convert to fraction form
    1,247.22/1,721.14 = 687.71/x
  3. Step 3: Cross multiply
    1,247.22x = 1,721.14 × 687.71
  4. Step 4: Simplify right side
    1,247.22x = 1,183,647.77
  5. Step 5: Solve for x
    x = 1,183,647.77/1,247.22
  6. Step 6: Final answer
    x = 949.03

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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.