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Finding the Fourth Proportional to 1,428.59, 2,142.89 and 388.59

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Solution

The fourth proportional to 1,428.59, 2,142.89 and 388.59 is: 582.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.59 : 2,142.89 = 388.59 : x
  2. Step 2: Convert to fraction form
    1,428.59/2,142.89 = 388.59/x
  3. Step 3: Cross multiply
    1,428.59x = 2,142.89 × 388.59
  4. Step 4: Simplify right side
    1,428.59x = 832,703.68
  5. Step 5: Solve for x
    x = 832,703.68/1,428.59
  6. Step 6: Final answer
    x = 582.88

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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.