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Finding the Fourth Proportional to 665.28, 918.38 and 399.84

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Solution

The fourth proportional to 665.28, 918.38 and 399.84 is: 551.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.28 : 918.38 = 399.84 : x
  2. Step 2: Convert to fraction form
    665.28/918.38 = 399.84/x
  3. Step 3: Cross multiply
    665.28x = 918.38 × 399.84
  4. Step 4: Simplify right side
    665.28x = 367,205.06
  5. Step 5: Solve for x
    x = 367,205.06/665.28
  6. Step 6: Final answer
    x = 551.96

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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.