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Finding the Fourth Proportional to 309.12, 428.42 and 303.36

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Solution

The fourth proportional to 309.12, 428.42 and 303.36 is: 420.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.12 : 428.42 = 303.36 : x
  2. Step 2: Convert to fraction form
    309.12/428.42 = 303.36/x
  3. Step 3: Cross multiply
    309.12x = 428.42 × 303.36
  4. Step 4: Simplify right side
    309.12x = 129,965.49
  5. Step 5: Solve for x
    x = 129,965.49/309.12
  6. Step 6: Final answer
    x = 420.44

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.