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Finding the Fourth Proportional to 102.92, 155.08 and 85.28

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Solution

The fourth proportional to 102.92, 155.08 and 85.28 is: 128.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.92 : 155.08 = 85.28 : x
  2. Step 2: Convert to fraction form
    102.92/155.08 = 85.28/x
  3. Step 3: Cross multiply
    102.92x = 155.08 × 85.28
  4. Step 4: Simplify right side
    102.92x = 13,225.22
  5. Step 5: Solve for x
    x = 13,225.22/102.92
  6. Step 6: Final answer
    x = 128.50

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.