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Finding the Fourth Proportional to 1,293.89, 1,940.84 and 428.21

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Solution

The fourth proportional to 1,293.89, 1,940.84 and 428.21 is: 642.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,293.89 : 1,940.84 = 428.21 : x
  2. Step 2: Convert to fraction form
    1,293.89/1,940.84 = 428.21/x
  3. Step 3: Cross multiply
    1,293.89x = 1,940.84 × 428.21
  4. Step 4: Simplify right side
    1,293.89x = 831,078.46
  5. Step 5: Solve for x
    x = 831,078.46/1,293.89
  6. Step 6: Final answer
    x = 642.31

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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.