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Finding the Fourth Proportional to 77.80, 116.21 and 65.80

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Solution

The fourth proportional to 77.80, 116.21 and 65.80 is: 98.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.80 : 116.21 = 65.80 : x
  2. Step 2: Convert to fraction form
    77.80/116.21 = 65.80/x
  3. Step 3: Cross multiply
    77.80x = 116.21 × 65.80
  4. Step 4: Simplify right side
    77.80x = 7,646.62
  5. Step 5: Solve for x
    x = 7,646.62/77.80
  6. Step 6: Final answer
    x = 98.29

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.