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Finding the Fourth Proportional to 1,428.89, 2,143.46 and 388.90

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Solution

The fourth proportional to 1,428.89, 2,143.46 and 388.90 is: 583.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.89 : 2,143.46 = 388.90 : x
  2. Step 2: Convert to fraction form
    1,428.89/2,143.46 = 388.90/x
  3. Step 3: Cross multiply
    1,428.89x = 2,143.46 × 388.90
  4. Step 4: Simplify right side
    1,428.89x = 833,595.25
  5. Step 5: Solve for x
    x = 833,595.25/1,428.89
  6. Step 6: Final answer
    x = 583.39

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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.