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Finding the Fourth Proportional to 390.36, 538.67 and 213.31

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Solution

The fourth proportional to 390.36, 538.67 and 213.31 is: 294.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.36 : 538.67 = 213.31 : x
  2. Step 2: Convert to fraction form
    390.36/538.67 = 213.31/x
  3. Step 3: Cross multiply
    390.36x = 538.67 × 213.31
  4. Step 4: Simplify right side
    390.36x = 114,902.88
  5. Step 5: Solve for x
    x = 114,902.88/390.36
  6. Step 6: Final answer
    x = 294.35

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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.