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Finding the Fourth Proportional to 312.80, 431.80 and 208.07

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Solution

The fourth proportional to 312.80, 431.80 and 208.07 is: 287.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.80 : 431.80 = 208.07 : x
  2. Step 2: Convert to fraction form
    312.80/431.80 = 208.07/x
  3. Step 3: Cross multiply
    312.80x = 431.80 × 208.07
  4. Step 4: Simplify right side
    312.80x = 89,843.57
  5. Step 5: Solve for x
    x = 89,843.57/312.80
  6. Step 6: Final answer
    x = 287.23

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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.