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Finding the Fourth Proportional to 305.90, 421.30 and 290.26

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Solution

The fourth proportional to 305.90, 421.30 and 290.26 is: 399.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.90 : 421.30 = 290.26 : x
  2. Step 2: Convert to fraction form
    305.90/421.30 = 290.26/x
  3. Step 3: Cross multiply
    305.90x = 421.30 × 290.26
  4. Step 4: Simplify right side
    305.90x = 122,286.54
  5. Step 5: Solve for x
    x = 122,286.54/305.90
  6. Step 6: Final answer
    x = 399.76

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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.