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Finding the Fourth Proportional to 77.21, 106.44 and 72.75

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Solution

The fourth proportional to 77.21, 106.44 and 72.75 is: 100.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.21 : 106.44 = 72.75 : x
  2. Step 2: Convert to fraction form
    77.21/106.44 = 72.75/x
  3. Step 3: Cross multiply
    77.21x = 106.44 × 72.75
  4. Step 4: Simplify right side
    77.21x = 7,743.51
  5. Step 5: Solve for x
    x = 7,743.51/77.21
  6. Step 6: Final answer
    x = 100.29

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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.