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Finding the Fourth Proportional to 89.02, 121.90 and 85.58

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Solution

The fourth proportional to 89.02, 121.90 and 85.58 is: 117.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.02 : 121.90 = 85.58 : x
  2. Step 2: Convert to fraction form
    89.02/121.90 = 85.58/x
  3. Step 3: Cross multiply
    89.02x = 121.90 × 85.58
  4. Step 4: Simplify right side
    89.02x = 10,432.20
  5. Step 5: Solve for x
    x = 10,432.20/89.02
  6. Step 6: Final answer
    x = 117.19

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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.