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Finding the Fourth Proportional to 839.56, 1,260.12 and 428.99

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Solution

The fourth proportional to 839.56, 1,260.12 and 428.99 is: 643.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.56 : 1,260.12 = 428.99 : x
  2. Step 2: Convert to fraction form
    839.56/1,260.12 = 428.99/x
  3. Step 3: Cross multiply
    839.56x = 1,260.12 × 428.99
  4. Step 4: Simplify right side
    839.56x = 540,577.30
  5. Step 5: Solve for x
    x = 540,577.30/839.56
  6. Step 6: Final answer
    x = 643.88

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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.