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Finding the Fourth Proportional to 77.42, 106.65 and 65.18

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Solution

The fourth proportional to 77.42, 106.65 and 65.18 is: 89.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.42 : 106.65 = 65.18 : x
  2. Step 2: Convert to fraction form
    77.42/106.65 = 65.18/x
  3. Step 3: Cross multiply
    77.42x = 106.65 × 65.18
  4. Step 4: Simplify right side
    77.42x = 6,951.45
  5. Step 5: Solve for x
    x = 6,951.45/77.42
  6. Step 6: Final answer
    x = 89.79

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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.