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Finding the Fourth Proportional to 312.82, 431.44 and 305.31

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Solution

The fourth proportional to 312.82, 431.44 and 305.31 is: 421.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.82 : 431.44 = 305.31 : x
  2. Step 2: Convert to fraction form
    312.82/431.44 = 305.31/x
  3. Step 3: Cross multiply
    312.82x = 431.44 × 305.31
  4. Step 4: Simplify right side
    312.82x = 131,722.95
  5. Step 5: Solve for x
    x = 131,722.95/312.82
  6. Step 6: Final answer
    x = 421.08

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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.