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Finding the Fourth Proportional to 1,428.78, 2,143.05 and 388.91

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Solution

The fourth proportional to 1,428.78, 2,143.05 and 388.91 is: 583.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.78 : 2,143.05 = 388.91 : x
  2. Step 2: Convert to fraction form
    1,428.78/2,143.05 = 388.91/x
  3. Step 3: Cross multiply
    1,428.78x = 2,143.05 × 388.91
  4. Step 4: Simplify right side
    1,428.78x = 833,453.58
  5. Step 5: Solve for x
    x = 833,453.58/1,428.78
  6. Step 6: Final answer
    x = 583.33

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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.