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Finding the Fourth Proportional to 208.55, 287.80 and 138.48

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Solution

The fourth proportional to 208.55, 287.80 and 138.48 is: 191.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.55 : 287.80 = 138.48 : x
  2. Step 2: Convert to fraction form
    208.55/287.80 = 138.48/x
  3. Step 3: Cross multiply
    208.55x = 287.80 × 138.48
  4. Step 4: Simplify right side
    208.55x = 39,854.20
  5. Step 5: Solve for x
    x = 39,854.20/208.55
  6. Step 6: Final answer
    x = 191.11

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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.