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Finding the Fourth Proportional to 665.28, 918.20 and 403.31

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Solution

The fourth proportional to 665.28, 918.20 and 403.31 is: 556.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.28 : 918.20 = 403.31 : x
  2. Step 2: Convert to fraction form
    665.28/918.20 = 403.31/x
  3. Step 3: Cross multiply
    665.28x = 918.20 × 403.31
  4. Step 4: Simplify right side
    665.28x = 370,322.55
  5. Step 5: Solve for x
    x = 370,322.55/665.28
  6. Step 6: Final answer
    x = 556.64

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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.