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Finding the Fourth Proportional to 661.86, 913.14 and 399.69

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Solution

The fourth proportional to 661.86, 913.14 and 399.69 is: 551.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.86 : 913.14 = 399.69 : x
  2. Step 2: Convert to fraction form
    661.86/913.14 = 399.69/x
  3. Step 3: Cross multiply
    661.86x = 913.14 × 399.69
  4. Step 4: Simplify right side
    661.86x = 364,972.93
  5. Step 5: Solve for x
    x = 364,972.93/661.86
  6. Step 6: Final answer
    x = 551.44

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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.