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Finding the Fourth Proportional to 312.58, 431.27 and 202.21

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Solution

The fourth proportional to 312.58, 431.27 and 202.21 is: 278.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.58 : 431.27 = 202.21 : x
  2. Step 2: Convert to fraction form
    312.58/431.27 = 202.21/x
  3. Step 3: Cross multiply
    312.58x = 431.27 × 202.21
  4. Step 4: Simplify right side
    312.58x = 87,207.11
  5. Step 5: Solve for x
    x = 87,207.11/312.58
  6. Step 6: Final answer
    x = 278.99

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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.