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Finding the Fourth Proportional to 431.39, 643.96 and 399.27

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Solution

The fourth proportional to 431.39, 643.96 and 399.27 is: 596.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.39 : 643.96 = 399.27 : x
  2. Step 2: Convert to fraction form
    431.39/643.96 = 399.27/x
  3. Step 3: Cross multiply
    431.39x = 643.96 × 399.27
  4. Step 4: Simplify right side
    431.39x = 257,116.82
  5. Step 5: Solve for x
    x = 257,116.82/431.39
  6. Step 6: Final answer
    x = 596.02

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.