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Finding the Fourth Proportional to 89.04, 121.60 and 85.20

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Solution

The fourth proportional to 89.04, 121.60 and 85.20 is: 116.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.04 : 121.60 = 85.20 : x
  2. Step 2: Convert to fraction form
    89.04/121.60 = 85.20/x
  3. Step 3: Cross multiply
    89.04x = 121.60 × 85.20
  4. Step 4: Simplify right side
    89.04x = 10,360.32
  5. Step 5: Solve for x
    x = 10,360.32/89.04
  6. Step 6: Final answer
    x = 116.36

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.