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Finding the Fourth Proportional to 121.49, 182.08 and 78.20

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Solution

The fourth proportional to 121.49, 182.08 and 78.20 is: 117.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.49 : 182.08 = 78.20 : x
  2. Step 2: Convert to fraction form
    121.49/182.08 = 78.20/x
  3. Step 3: Cross multiply
    121.49x = 182.08 × 78.20
  4. Step 4: Simplify right side
    121.49x = 14,238.66
  5. Step 5: Solve for x
    x = 14,238.66/121.49
  6. Step 6: Final answer
    x = 117.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.