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Finding the Fourth Proportional to 390.94, 538.89 and 285.88

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Solution

The fourth proportional to 390.94, 538.89 and 285.88 is: 394.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 538.89 = 285.88 : x
  2. Step 2: Convert to fraction form
    390.94/538.89 = 285.88/x
  3. Step 3: Cross multiply
    390.94x = 538.89 × 285.88
  4. Step 4: Simplify right side
    390.94x = 154,057.87
  5. Step 5: Solve for x
    x = 154,057.87/390.94
  6. Step 6: Final answer
    x = 394.07

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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.