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Finding the Fourth Proportional to 77.28, 106.21 and 66.30

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Solution

The fourth proportional to 77.28, 106.21 and 66.30 is: 91.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.28 : 106.21 = 66.30 : x
  2. Step 2: Convert to fraction form
    77.28/106.21 = 66.30/x
  3. Step 3: Cross multiply
    77.28x = 106.21 × 66.30
  4. Step 4: Simplify right side
    77.28x = 7,041.72
  5. Step 5: Solve for x
    x = 7,041.72/77.28
  6. Step 6: Final answer
    x = 91.12

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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.