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Finding the Fourth Proportional to 661.07, 991.69 and 198.86

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Solution

The fourth proportional to 661.07, 991.69 and 198.86 is: 298.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.07 : 991.69 = 198.86 : x
  2. Step 2: Convert to fraction form
    661.07/991.69 = 198.86/x
  3. Step 3: Cross multiply
    661.07x = 991.69 × 198.86
  4. Step 4: Simplify right side
    661.07x = 197,202.02
  5. Step 5: Solve for x
    x = 197,202.02/661.07
  6. Step 6: Final answer
    x = 298.31

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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.