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Finding the Fourth Proportional to 828.80, 1,243.20 and 672.20

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Solution

The fourth proportional to 828.80, 1,243.20 and 672.20 is: 1,008.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.80 : 1,243.20 = 672.20 : x
  2. Step 2: Convert to fraction form
    828.80/1,243.20 = 672.20/x
  3. Step 3: Cross multiply
    828.80x = 1,243.20 × 672.20
  4. Step 4: Simplify right side
    828.80x = 835,679.04
  5. Step 5: Solve for x
    x = 835,679.04/828.80
  6. Step 6: Final answer
    x = 1,008.30

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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.