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Finding the Fourth Proportional to 120.60, 180 and 105.12

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Solution

The fourth proportional to 120.60, 180 and 105.12 is: 156.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.60 : 180 = 105.12 : x
  2. Step 2: Convert to fraction form
    120.60/180 = 105.12/x
  3. Step 3: Cross multiply
    120.60x = 180 × 105.12
  4. Step 4: Simplify right side
    120.60x = 18,921.60
  5. Step 5: Solve for x
    x = 18,921.60/120.60
  6. Step 6: Final answer
    x = 156.90

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.