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Finding the Fourth Proportional to 427.64, 639.83 and 393.21

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Solution

The fourth proportional to 427.64, 639.83 and 393.21 is: 588.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.64 : 639.83 = 393.21 : x
  2. Step 2: Convert to fraction form
    427.64/639.83 = 393.21/x
  3. Step 3: Cross multiply
    427.64x = 639.83 × 393.21
  4. Step 4: Simplify right side
    427.64x = 251,588.54
  5. Step 5: Solve for x
    x = 251,588.54/427.64
  6. Step 6: Final answer
    x = 588.33

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.