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Finding the Fourth Proportional to 661.62, 913.08 and 399.72

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Solution

The fourth proportional to 661.62, 913.08 and 399.72 is: 551.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.62 : 913.08 = 399.72 : x
  2. Step 2: Convert to fraction form
    661.62/913.08 = 399.72/x
  3. Step 3: Cross multiply
    661.62x = 913.08 × 399.72
  4. Step 4: Simplify right side
    661.62x = 364,976.34
  5. Step 5: Solve for x
    x = 364,976.34/661.62
  6. Step 6: Final answer
    x = 551.64

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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.