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Finding the Fourth Proportional to 77.68, 115.90 and 70

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Solution

The fourth proportional to 77.68, 115.90 and 70 is: 104.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.68 : 115.90 = 70 : x
  2. Step 2: Convert to fraction form
    77.68/115.90 = 70/x
  3. Step 3: Cross multiply
    77.68x = 115.90 × 70
  4. Step 4: Simplify right side
    77.68x = 8,113
  5. Step 5: Solve for x
    x = 8,113/77.68
  6. Step 6: Final answer
    x = 104.44

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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.