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Finding the Fourth Proportional to 208.71, 288.15 and 135.21

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Solution

The fourth proportional to 208.71, 288.15 and 135.21 is: 186.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.71 : 288.15 = 135.21 : x
  2. Step 2: Convert to fraction form
    208.71/288.15 = 135.21/x
  3. Step 3: Cross multiply
    208.71x = 288.15 × 135.21
  4. Step 4: Simplify right side
    208.71x = 38,960.76
  5. Step 5: Solve for x
    x = 38,960.76/208.71
  6. Step 6: Final answer
    x = 186.67

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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.