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Finding the Fourth Proportional to 661.62, 913.11 and 399.63

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Solution

The fourth proportional to 661.62, 913.11 and 399.63 is: 551.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.62 : 913.11 = 399.63 : x
  2. Step 2: Convert to fraction form
    661.62/913.11 = 399.63/x
  3. Step 3: Cross multiply
    661.62x = 913.11 × 399.63
  4. Step 4: Simplify right side
    661.62x = 364,906.15
  5. Step 5: Solve for x
    x = 364,906.15/661.62
  6. Step 6: Final answer
    x = 551.53

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.