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Finding the Fourth Proportional to 390.99, 539.66 and 243.54

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Solution

The fourth proportional to 390.99, 539.66 and 243.54 is: 336.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.99 : 539.66 = 243.54 : x
  2. Step 2: Convert to fraction form
    390.99/539.66 = 243.54/x
  3. Step 3: Cross multiply
    390.99x = 539.66 × 243.54
  4. Step 4: Simplify right side
    390.99x = 131,428.80
  5. Step 5: Solve for x
    x = 131,428.80/390.99
  6. Step 6: Final answer
    x = 336.14

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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.