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Finding the Fourth Proportional to 661.10, 991.60 and 198.86

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Solution

The fourth proportional to 661.10, 991.60 and 198.86 is: 298.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.10 : 991.60 = 198.86 : x
  2. Step 2: Convert to fraction form
    661.10/991.60 = 198.86/x
  3. Step 3: Cross multiply
    661.10x = 991.60 × 198.86
  4. Step 4: Simplify right side
    661.10x = 197,192.55
  5. Step 5: Solve for x
    x = 197,192.55/661.10
  6. Step 6: Final answer
    x = 298.28

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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.