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Finding the Fourth Proportional to 312.91, 431.80 and 181.90

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Solution

The fourth proportional to 312.91, 431.80 and 181.90 is: 251.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.91 : 431.80 = 181.90 : x
  2. Step 2: Convert to fraction form
    312.91/431.80 = 181.90/x
  3. Step 3: Cross multiply
    312.91x = 431.80 × 181.90
  4. Step 4: Simplify right side
    312.91x = 78,544.42
  5. Step 5: Solve for x
    x = 78,544.42/312.91
  6. Step 6: Final answer
    x = 251.01

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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.