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Finding the Fourth Proportional to 390.94, 539.31 and 243.75

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Solution

The fourth proportional to 390.94, 539.31 and 243.75 is: 336.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 539.31 = 243.75 : x
  2. Step 2: Convert to fraction form
    390.94/539.31 = 243.75/x
  3. Step 3: Cross multiply
    390.94x = 539.31 × 243.75
  4. Step 4: Simplify right side
    390.94x = 131,454.12
  5. Step 5: Solve for x
    x = 131,454.12/390.94
  6. Step 6: Final answer
    x = 336.25

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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.