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Finding the Fourth Proportional to 661.20, 991.16 and 314.72

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Solution

The fourth proportional to 661.20, 991.16 and 314.72 is: 471.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 991.16 = 314.72 : x
  2. Step 2: Convert to fraction form
    661.20/991.16 = 314.72/x
  3. Step 3: Cross multiply
    661.20x = 991.16 × 314.72
  4. Step 4: Simplify right side
    661.20x = 311,937.88
  5. Step 5: Solve for x
    x = 311,937.88/661.20
  6. Step 6: Final answer
    x = 471.78

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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.