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Finding the Fourth Proportional to 306.99, 420.57 and 290.61

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Solution

The fourth proportional to 306.99, 420.57 and 290.61 is: 398.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    306.99 : 420.57 = 290.61 : x
  2. Step 2: Convert to fraction form
    306.99/420.57 = 290.61/x
  3. Step 3: Cross multiply
    306.99x = 420.57 × 290.61
  4. Step 4: Simplify right side
    306.99x = 122,221.85
  5. Step 5: Solve for x
    x = 122,221.85/306.99
  6. Step 6: Final answer
    x = 398.13

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.