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Finding the Fourth Proportional to 661, 991.28 and 198.76

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Solution

The fourth proportional to 661, 991.28 and 198.76 is: 298.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    661 : 991.28 = 198.76 : x
  2. Step 2: Convert to fraction form
    661/991.28 = 198.76/x
  3. Step 3: Cross multiply
    661x = 991.28 × 198.76
  4. Step 4: Simplify right side
    661x = 197,026.81
  5. Step 5: Solve for x
    x = 197,026.81/661
  6. Step 6: Final answer
    x = 298.07

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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.