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Finding the Fourth Proportional to 85.22, 128.28 and 74.05

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Solution

The fourth proportional to 85.22, 128.28 and 74.05 is: 111.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.22 : 128.28 = 74.05 : x
  2. Step 2: Convert to fraction form
    85.22/128.28 = 74.05/x
  3. Step 3: Cross multiply
    85.22x = 128.28 × 74.05
  4. Step 4: Simplify right side
    85.22x = 9,499.09
  5. Step 5: Solve for x
    x = 9,499.09/85.22
  6. Step 6: Final answer
    x = 111.47

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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.