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Finding the Fourth Proportional to 390.95, 539.69 and 243.69

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Solution

The fourth proportional to 390.95, 539.69 and 243.69 is: 336.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.95 : 539.69 = 243.69 : x
  2. Step 2: Convert to fraction form
    390.95/539.69 = 243.69/x
  3. Step 3: Cross multiply
    390.95x = 539.69 × 243.69
  4. Step 4: Simplify right side
    390.95x = 131,513.14
  5. Step 5: Solve for x
    x = 131,513.14/390.95
  6. Step 6: Final answer
    x = 336.39

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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.