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Finding the Fourth Proportional to 815, 1,122.72 and 618.32

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Solution

The fourth proportional to 815, 1,122.72 and 618.32 is: 851.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    815 : 1,122.72 = 618.32 : x
  2. Step 2: Convert to fraction form
    815/1,122.72 = 618.32/x
  3. Step 3: Cross multiply
    815x = 1,122.72 × 618.32
  4. Step 4: Simplify right side
    815x = 694,200.23
  5. Step 5: Solve for x
    x = 694,200.23/815
  6. Step 6: Final answer
    x = 851.78

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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.