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Finding the Fourth Proportional to 208.81, 287.84 and 138.74

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Solution

The fourth proportional to 208.81, 287.84 and 138.74 is: 191.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.81 : 287.84 = 138.74 : x
  2. Step 2: Convert to fraction form
    208.81/287.84 = 138.74/x
  3. Step 3: Cross multiply
    208.81x = 287.84 × 138.74
  4. Step 4: Simplify right side
    208.81x = 39,934.23
  5. Step 5: Solve for x
    x = 39,934.23/208.81
  6. Step 6: Final answer
    x = 191.25

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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.