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Finding the Fourth Proportional to 855.24, 1,287.42 and 661.28

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Solution

The fourth proportional to 855.24, 1,287.42 and 661.28 is: 995.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.24 : 1,287.42 = 661.28 : x
  2. Step 2: Convert to fraction form
    855.24/1,287.42 = 661.28/x
  3. Step 3: Cross multiply
    855.24x = 1,287.42 × 661.28
  4. Step 4: Simplify right side
    855.24x = 851,338.66
  5. Step 5: Solve for x
    x = 851,338.66/855.24
  6. Step 6: Final answer
    x = 995.44

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.