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Finding the Fourth Proportional to 871.14, 1,297.92 and 815.28

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Solution

The fourth proportional to 871.14, 1,297.92 and 815.28 is: 1,214.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.14 : 1,297.92 = 815.28 : x
  2. Step 2: Convert to fraction form
    871.14/1,297.92 = 815.28/x
  3. Step 3: Cross multiply
    871.14x = 1,297.92 × 815.28
  4. Step 4: Simplify right side
    871.14x = 1,058,168.22
  5. Step 5: Solve for x
    x = 1,058,168.22/871.14
  6. Step 6: Final answer
    x = 1,214.69

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.