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Finding the Fourth Proportional to 79.65, 119.70 and 78.84

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Solution

The fourth proportional to 79.65, 119.70 and 78.84 is: 118.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.65 : 119.70 = 78.84 : x
  2. Step 2: Convert to fraction form
    79.65/119.70 = 78.84/x
  3. Step 3: Cross multiply
    79.65x = 119.70 × 78.84
  4. Step 4: Simplify right side
    79.65x = 9,437.15
  5. Step 5: Solve for x
    x = 9,437.15/79.65
  6. Step 6: Final answer
    x = 118.48

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Why These Related Problems?

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