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Finding the Fourth Proportional to 828.80, 1,243.80 and 647.75

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Solution

The fourth proportional to 828.80, 1,243.80 and 647.75 is: 972.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.80 : 1,243.80 = 647.75 : x
  2. Step 2: Convert to fraction form
    828.80/1,243.80 = 647.75/x
  3. Step 3: Cross multiply
    828.80x = 1,243.80 × 647.75
  4. Step 4: Simplify right side
    828.80x = 805,671.45
  5. Step 5: Solve for x
    x = 805,671.45/828.80
  6. Step 6: Final answer
    x = 972.09

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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.