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Finding the Fourth Proportional to 865.74, 1,295.80 and 820.64

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Solution

The fourth proportional to 865.74, 1,295.80 and 820.64 is: 1,228.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.74 : 1,295.80 = 820.64 : x
  2. Step 2: Convert to fraction form
    865.74/1,295.80 = 820.64/x
  3. Step 3: Cross multiply
    865.74x = 1,295.80 × 820.64
  4. Step 4: Simplify right side
    865.74x = 1,063,380.12
  5. Step 5: Solve for x
    x = 1,063,380.12/865.74
  6. Step 6: Final answer
    x = 1,228.28

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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.