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Finding the Fourth Proportional to 661.18, 991.65 and 198.85

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Solution

The fourth proportional to 661.18, 991.65 and 198.85 is: 298.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.18 : 991.65 = 198.85 : x
  2. Step 2: Convert to fraction form
    661.18/991.65 = 198.85/x
  3. Step 3: Cross multiply
    661.18x = 991.65 × 198.85
  4. Step 4: Simplify right side
    661.18x = 197,189.60
  5. Step 5: Solve for x
    x = 197,189.60/661.18
  6. Step 6: Final answer
    x = 298.24

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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.