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Finding the Fourth Proportional to 77.50, 106.74 and 72.12

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Solution

The fourth proportional to 77.50, 106.74 and 72.12 is: 99.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.50 : 106.74 = 72.12 : x
  2. Step 2: Convert to fraction form
    77.50/106.74 = 72.12/x
  3. Step 3: Cross multiply
    77.50x = 106.74 × 72.12
  4. Step 4: Simplify right side
    77.50x = 7,698.09
  5. Step 5: Solve for x
    x = 7,698.09/77.50
  6. Step 6: Final answer
    x = 99.33

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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.