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Finding the Fourth Proportional to 89.16, 122.90 and 72.84

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Solution

The fourth proportional to 89.16, 122.90 and 72.84 is: 100.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.16 : 122.90 = 72.84 : x
  2. Step 2: Convert to fraction form
    89.16/122.90 = 72.84/x
  3. Step 3: Cross multiply
    89.16x = 122.90 × 72.84
  4. Step 4: Simplify right side
    89.16x = 8,952.04
  5. Step 5: Solve for x
    x = 8,952.04/89.16
  6. Step 6: Final answer
    x = 100.40

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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.