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Finding the Fourth Proportional to 85.51, 128.08 and 71.03

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Solution

The fourth proportional to 85.51, 128.08 and 71.03 is: 106.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.51 : 128.08 = 71.03 : x
  2. Step 2: Convert to fraction form
    85.51/128.08 = 71.03/x
  3. Step 3: Cross multiply
    85.51x = 128.08 × 71.03
  4. Step 4: Simplify right side
    85.51x = 9,096.53
  5. Step 5: Solve for x
    x = 9,096.53/85.51
  6. Step 6: Final answer
    x = 106.39

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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.