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Finding the Fourth Proportional to 208.16, 287.20 and 120.80

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Solution

The fourth proportional to 208.16, 287.20 and 120.80 is: 166.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.16 : 287.20 = 120.80 : x
  2. Step 2: Convert to fraction form
    208.16/287.20 = 120.80/x
  3. Step 3: Cross multiply
    208.16x = 287.20 × 120.80
  4. Step 4: Simplify right side
    208.16x = 34,693.76
  5. Step 5: Solve for x
    x = 34,693.76/208.16
  6. Step 6: Final answer
    x = 166.67

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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.