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Finding the Fourth Proportional to 390.86, 539.40 and 213.82

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Solution

The fourth proportional to 390.86, 539.40 and 213.82 is: 295.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.86 : 539.40 = 213.82 : x
  2. Step 2: Convert to fraction form
    390.86/539.40 = 213.82/x
  3. Step 3: Cross multiply
    390.86x = 539.40 × 213.82
  4. Step 4: Simplify right side
    390.86x = 115,334.51
  5. Step 5: Solve for x
    x = 115,334.51/390.86
  6. Step 6: Final answer
    x = 295.08

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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.