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Finding the Fourth Proportional to 208.63, 287.80 and 137.70

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Solution

The fourth proportional to 208.63, 287.80 and 137.70 is: 189.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.63 : 287.80 = 137.70 : x
  2. Step 2: Convert to fraction form
    208.63/287.80 = 137.70/x
  3. Step 3: Cross multiply
    208.63x = 287.80 × 137.70
  4. Step 4: Simplify right side
    208.63x = 39,630.49
  5. Step 5: Solve for x
    x = 39,630.49/208.63
  6. Step 6: Final answer
    x = 189.96

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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.