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Finding the Fourth Proportional to 208.21, 287.40 and 120.91

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Solution

The fourth proportional to 208.21, 287.40 and 120.91 is: 166.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.21 : 287.40 = 120.91 : x
  2. Step 2: Convert to fraction form
    208.21/287.40 = 120.91/x
  3. Step 3: Cross multiply
    208.21x = 287.40 × 120.91
  4. Step 4: Simplify right side
    208.21x = 34,749.53
  5. Step 5: Solve for x
    x = 34,749.53/208.21
  6. Step 6: Final answer
    x = 166.90

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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.