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Finding the Fourth Proportional to 947.83, 1,422.20 and 428.20

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Solution

The fourth proportional to 947.83, 1,422.20 and 428.20 is: 642.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.83 : 1,422.20 = 428.20 : x
  2. Step 2: Convert to fraction form
    947.83/1,422.20 = 428.20/x
  3. Step 3: Cross multiply
    947.83x = 1,422.20 × 428.20
  4. Step 4: Simplify right side
    947.83x = 608,976.79
  5. Step 5: Solve for x
    x = 608,976.79/947.83
  6. Step 6: Final answer
    x = 642.50

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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.