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Finding the Fourth Proportional to 208.99, 288.21 and 138.07

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Solution

The fourth proportional to 208.99, 288.21 and 138.07 is: 190.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.99 : 288.21 = 138.07 : x
  2. Step 2: Convert to fraction form
    208.99/288.21 = 138.07/x
  3. Step 3: Cross multiply
    208.99x = 288.21 × 138.07
  4. Step 4: Simplify right side
    208.99x = 39,793.15
  5. Step 5: Solve for x
    x = 39,793.15/208.99
  6. Step 6: Final answer
    x = 190.41

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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.