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Finding the Fourth Proportional to 77.85, 107.51 and 65.61

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Solution

The fourth proportional to 77.85, 107.51 and 65.61 is: 90.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.85 : 107.51 = 65.61 : x
  2. Step 2: Convert to fraction form
    77.85/107.51 = 65.61/x
  3. Step 3: Cross multiply
    77.85x = 107.51 × 65.61
  4. Step 4: Simplify right side
    77.85x = 7,053.40
  5. Step 5: Solve for x
    x = 7,053.40/77.85
  6. Step 6: Final answer
    x = 90.60

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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.