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Finding the Fourth Proportional to 85.44, 128.02 and 70.86

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Solution

The fourth proportional to 85.44, 128.02 and 70.86 is: 106.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.44 : 128.02 = 70.86 : x
  2. Step 2: Convert to fraction form
    85.44/128.02 = 70.86/x
  3. Step 3: Cross multiply
    85.44x = 128.02 × 70.86
  4. Step 4: Simplify right side
    85.44x = 9,071.50
  5. Step 5: Solve for x
    x = 9,071.50/85.44
  6. Step 6: Final answer
    x = 106.17

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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.