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Finding the Fourth Proportional to 290.12, 399.56 and 280.12

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Solution

The fourth proportional to 290.12, 399.56 and 280.12 is: 385.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    290.12 : 399.56 = 280.12 : x
  2. Step 2: Convert to fraction form
    290.12/399.56 = 280.12/x
  3. Step 3: Cross multiply
    290.12x = 399.56 × 280.12
  4. Step 4: Simplify right side
    290.12x = 111,924.75
  5. Step 5: Solve for x
    x = 111,924.75/290.12
  6. Step 6: Final answer
    x = 385.79

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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.