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Finding the Fourth Proportional to 839.56, 1,259.46 and 428.96

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Solution

The fourth proportional to 839.56, 1,259.46 and 428.96 is: 643.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.56 : 1,259.46 = 428.96 : x
  2. Step 2: Convert to fraction form
    839.56/1,259.46 = 428.96/x
  3. Step 3: Cross multiply
    839.56x = 1,259.46 × 428.96
  4. Step 4: Simplify right side
    839.56x = 540,257.96
  5. Step 5: Solve for x
    x = 540,257.96/839.56
  6. Step 6: Final answer
    x = 643.50

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Double scale
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1.5x scale

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.