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Finding the Fourth Proportional to 661.30, 912.09 and 399.04

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Solution

The fourth proportional to 661.30, 912.09 and 399.04 is: 550.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.30 : 912.09 = 399.04 : x
  2. Step 2: Convert to fraction form
    661.30/912.09 = 399.04/x
  3. Step 3: Cross multiply
    661.30x = 912.09 × 399.04
  4. Step 4: Simplify right side
    661.30x = 363,960.39
  5. Step 5: Solve for x
    x = 363,960.39/661.30
  6. Step 6: Final answer
    x = 550.37

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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.