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Finding the Fourth Proportional to 76.95, 106.21 and 70.80

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Solution

The fourth proportional to 76.95, 106.21 and 70.80 is: 97.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.95 : 106.21 = 70.80 : x
  2. Step 2: Convert to fraction form
    76.95/106.21 = 70.80/x
  3. Step 3: Cross multiply
    76.95x = 106.21 × 70.80
  4. Step 4: Simplify right side
    76.95x = 7,519.67
  5. Step 5: Solve for x
    x = 7,519.67/76.95
  6. Step 6: Final answer
    x = 97.72

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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.