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Finding the Fourth Proportional to 80.70, 120.95 and 78.57

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Solution

The fourth proportional to 80.70, 120.95 and 78.57 is: 117.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.70 : 120.95 = 78.57 : x
  2. Step 2: Convert to fraction form
    80.70/120.95 = 78.57/x
  3. Step 3: Cross multiply
    80.70x = 120.95 × 78.57
  4. Step 4: Simplify right side
    80.70x = 9,502.65
  5. Step 5: Solve for x
    x = 9,502.65/80.70
  6. Step 6: Final answer
    x = 117.75

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.