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Finding the Fourth Proportional to 170.40, 255.60 and 91.20

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Solution

The fourth proportional to 170.40, 255.60 and 91.20 is: 136.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    170.40 : 255.60 = 91.20 : x
  2. Step 2: Convert to fraction form
    170.40/255.60 = 91.20/x
  3. Step 3: Cross multiply
    170.40x = 255.60 × 91.20
  4. Step 4: Simplify right side
    170.40x = 23,310.72
  5. Step 5: Solve for x
    x = 23,310.72/170.40
  6. Step 6: Final answer
    x = 136.80

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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.