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Finding the Fourth Proportional to 821.28, 1,131.45 and 572.15

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Solution

The fourth proportional to 821.28, 1,131.45 and 572.15 is: 788.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.28 : 1,131.45 = 572.15 : x
  2. Step 2: Convert to fraction form
    821.28/1,131.45 = 572.15/x
  3. Step 3: Cross multiply
    821.28x = 1,131.45 × 572.15
  4. Step 4: Simplify right side
    821.28x = 647,359.80
  5. Step 5: Solve for x
    x = 647,359.80/821.28
  6. Step 6: Final answer
    x = 788.23

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.