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Finding the Fourth Proportional to 661.22, 991.79 and 198.99

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Solution

The fourth proportional to 661.22, 991.79 and 198.99 is: 298.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.22 : 991.79 = 198.99 : x
  2. Step 2: Convert to fraction form
    661.22/991.79 = 198.99/x
  3. Step 3: Cross multiply
    661.22x = 991.79 × 198.99
  4. Step 4: Simplify right side
    661.22x = 197,356.04
  5. Step 5: Solve for x
    x = 197,356.04/661.22
  6. Step 6: Final answer
    x = 298.47

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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.