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Finding the Fourth Proportional to 170.64, 255.72 and 85.20

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Solution

The fourth proportional to 170.64, 255.72 and 85.20 is: 127.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    170.64 : 255.72 = 85.20 : x
  2. Step 2: Convert to fraction form
    170.64/255.72 = 85.20/x
  3. Step 3: Cross multiply
    170.64x = 255.72 × 85.20
  4. Step 4: Simplify right side
    170.64x = 21,787.34
  5. Step 5: Solve for x
    x = 21,787.34/170.64
  6. Step 6: Final answer
    x = 127.68

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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.