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Finding the Fourth Proportional to 661.99, 913.20 and 399.94

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Solution

The fourth proportional to 661.99, 913.20 and 399.94 is: 551.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.99 : 913.20 = 399.94 : x
  2. Step 2: Convert to fraction form
    661.99/913.20 = 399.94/x
  3. Step 3: Cross multiply
    661.99x = 913.20 × 399.94
  4. Step 4: Simplify right side
    661.99x = 365,225.21
  5. Step 5: Solve for x
    x = 365,225.21/661.99
  6. Step 6: Final answer
    x = 551.71

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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.