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Finding the Fourth Proportional to 989.91, 1,365.12 and 791.37

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Solution

The fourth proportional to 989.91, 1,365.12 and 791.37 is: 1,091.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.91 : 1,365.12 = 791.37 : x
  2. Step 2: Convert to fraction form
    989.91/1,365.12 = 791.37/x
  3. Step 3: Cross multiply
    989.91x = 1,365.12 × 791.37
  4. Step 4: Simplify right side
    989.91x = 1,080,315.01
  5. Step 5: Solve for x
    x = 1,080,315.01/989.91
  6. Step 6: Final answer
    x = 1,091.33

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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.