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Finding the Fourth Proportional to 130.60, 180.20 and 120.78

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Solution

The fourth proportional to 130.60, 180.20 and 120.78 is: 166.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.60 : 180.20 = 120.78 : x
  2. Step 2: Convert to fraction form
    130.60/180.20 = 120.78/x
  3. Step 3: Cross multiply
    130.60x = 180.20 × 120.78
  4. Step 4: Simplify right side
    130.60x = 21,764.18
  5. Step 5: Solve for x
    x = 21,764.18/130.60
  6. Step 6: Final answer
    x = 166.64

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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.