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Finding the Fourth Proportional to 77.80, 117.28 and 72.84

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Solution

The fourth proportional to 77.80, 117.28 and 72.84 is: 109.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.80 : 117.28 = 72.84 : x
  2. Step 2: Convert to fraction form
    77.80/117.28 = 72.84/x
  3. Step 3: Cross multiply
    77.80x = 117.28 × 72.84
  4. Step 4: Simplify right side
    77.80x = 8,542.68
  5. Step 5: Solve for x
    x = 8,542.68/77.80
  6. Step 6: Final answer
    x = 109.80

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.