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Finding the Fourth Proportional to 89.23, 123.21 and 87.81

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Solution

The fourth proportional to 89.23, 123.21 and 87.81 is: 121.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.23 : 123.21 = 87.81 : x
  2. Step 2: Convert to fraction form
    89.23/123.21 = 87.81/x
  3. Step 3: Cross multiply
    89.23x = 123.21 × 87.81
  4. Step 4: Simplify right side
    89.23x = 10,818.63
  5. Step 5: Solve for x
    x = 10,818.63/89.23
  6. Step 6: Final answer
    x = 121.24

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.