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Finding the Fourth Proportional to 128.20, 176.12 and 120.10

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Solution

The fourth proportional to 128.20, 176.12 and 120.10 is: 164.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.20 : 176.12 = 120.10 : x
  2. Step 2: Convert to fraction form
    128.20/176.12 = 120.10/x
  3. Step 3: Cross multiply
    128.20x = 176.12 × 120.10
  4. Step 4: Simplify right side
    128.20x = 21,152.01
  5. Step 5: Solve for x
    x = 21,152.01/128.20
  6. Step 6: Final answer
    x = 164.99

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.