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Finding the Fourth Proportional to 1,428.09, 2,142.20 and 388.09

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Solution

The fourth proportional to 1,428.09, 2,142.20 and 388.09 is: 582.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.09 : 2,142.20 = 388.09 : x
  2. Step 2: Convert to fraction form
    1,428.09/2,142.20 = 388.09/x
  3. Step 3: Cross multiply
    1,428.09x = 2,142.20 × 388.09
  4. Step 4: Simplify right side
    1,428.09x = 831,366.40
  5. Step 5: Solve for x
    x = 831,366.40/1,428.09
  6. Step 6: Final answer
    x = 582.15

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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.