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Finding the Fourth Proportional to 661.21, 991.79 and 271.11

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Solution

The fourth proportional to 661.21, 991.79 and 271.11 is: 406.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.21 : 991.79 = 271.11 : x
  2. Step 2: Convert to fraction form
    661.21/991.79 = 271.11/x
  3. Step 3: Cross multiply
    661.21x = 991.79 × 271.11
  4. Step 4: Simplify right side
    661.21x = 268,878.44
  5. Step 5: Solve for x
    x = 268,878.44/661.21
  6. Step 6: Final answer
    x = 406.64

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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.