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Finding the Fourth Proportional to 215.31, 320.88 and 208.71

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Solution

The fourth proportional to 215.31, 320.88 and 208.71 is: 311.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.31 : 320.88 = 208.71 : x
  2. Step 2: Convert to fraction form
    215.31/320.88 = 208.71/x
  3. Step 3: Cross multiply
    215.31x = 320.88 × 208.71
  4. Step 4: Simplify right side
    215.31x = 66,970.86
  5. Step 5: Solve for x
    x = 66,970.86/215.31
  6. Step 6: Final answer
    x = 311.04

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.