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Finding the Fourth Proportional to 661.20, 991.42 and 271.09

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Solution

The fourth proportional to 661.20, 991.42 and 271.09 is: 406.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 991.42 = 271.09 : x
  2. Step 2: Convert to fraction form
    661.20/991.42 = 271.09/x
  3. Step 3: Cross multiply
    661.20x = 991.42 × 271.09
  4. Step 4: Simplify right side
    661.20x = 268,764.05
  5. Step 5: Solve for x
    x = 268,764.05/661.20
  6. Step 6: Final answer
    x = 406.48

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1.5x scale

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.