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Finding the Fourth Proportional to 390.66, 539.12 and 213.63

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Solution

The fourth proportional to 390.66, 539.12 and 213.63 is: 294.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.66 : 539.12 = 213.63 : x
  2. Step 2: Convert to fraction form
    390.66/539.12 = 213.63/x
  3. Step 3: Cross multiply
    390.66x = 539.12 × 213.63
  4. Step 4: Simplify right side
    390.66x = 115,172.21
  5. Step 5: Solve for x
    x = 115,172.21/390.66
  6. Step 6: Final answer
    x = 294.81

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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.