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Finding the Fourth Proportional to 208.78, 288.19 and 142.50

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Solution

The fourth proportional to 208.78, 288.19 and 142.50 is: 196.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.78 : 288.19 = 142.50 : x
  2. Step 2: Convert to fraction form
    208.78/288.19 = 142.50/x
  3. Step 3: Cross multiply
    208.78x = 288.19 × 142.50
  4. Step 4: Simplify right side
    208.78x = 41,068.33
  5. Step 5: Solve for x
    x = 41,068.33/208.78
  6. Step 6: Final answer
    x = 196.71

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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.