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Finding the Fourth Proportional to 309.21, 426.35 and 287.34

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Solution

The fourth proportional to 309.21, 426.35 and 287.34 is: 396.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.21 : 426.35 = 287.34 : x
  2. Step 2: Convert to fraction form
    309.21/426.35 = 287.34/x
  3. Step 3: Cross multiply
    309.21x = 426.35 × 287.34
  4. Step 4: Simplify right side
    309.21x = 122,507.41
  5. Step 5: Solve for x
    x = 122,507.41/309.21
  6. Step 6: Final answer
    x = 396.19

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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.