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Finding the Fourth Proportional to 661.55, 913.01 and 399.56

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Solution

The fourth proportional to 661.55, 913.01 and 399.56 is: 551.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.55 : 913.01 = 399.56 : x
  2. Step 2: Convert to fraction form
    661.55/913.01 = 399.56/x
  3. Step 3: Cross multiply
    661.55x = 913.01 × 399.56
  4. Step 4: Simplify right side
    661.55x = 364,802.56
  5. Step 5: Solve for x
    x = 364,802.56/661.55
  6. Step 6: Final answer
    x = 551.43

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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.