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Finding the Fourth Proportional to 1,415, 2,121.22 and 721.28

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Solution

The fourth proportional to 1,415, 2,121.22 and 721.28 is: 1,081.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,415 : 2,121.22 = 721.28 : x
  2. Step 2: Convert to fraction form
    1,415/2,121.22 = 721.28/x
  3. Step 3: Cross multiply
    1,415x = 2,121.22 × 721.28
  4. Step 4: Simplify right side
    1,415x = 1,529,993.56
  5. Step 5: Solve for x
    x = 1,529,993.56/1,415
  6. Step 6: Final answer
    x = 1,081.27

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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.