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Finding the Fourth Proportional to 309.40, 426.18 and 256.84

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Solution

The fourth proportional to 309.40, 426.18 and 256.84 is: 353.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.40 : 426.18 = 256.84 : x
  2. Step 2: Convert to fraction form
    309.40/426.18 = 256.84/x
  3. Step 3: Cross multiply
    309.40x = 426.18 × 256.84
  4. Step 4: Simplify right side
    309.40x = 109,460.07
  5. Step 5: Solve for x
    x = 109,460.07/309.40
  6. Step 6: Final answer
    x = 353.78

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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.