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Finding the Fourth Proportional to 772.38, 1,157.22 and 643.21

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Solution

The fourth proportional to 772.38, 1,157.22 and 643.21 is: 963.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.38 : 1,157.22 = 643.21 : x
  2. Step 2: Convert to fraction form
    772.38/1,157.22 = 643.21/x
  3. Step 3: Cross multiply
    772.38x = 1,157.22 × 643.21
  4. Step 4: Simplify right side
    772.38x = 744,335.48
  5. Step 5: Solve for x
    x = 744,335.48/772.38
  6. Step 6: Final answer
    x = 963.69

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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.