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Finding the Fourth Proportional to 79.70, 119.30 and 78.30

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Solution

The fourth proportional to 79.70, 119.30 and 78.30 is: 117.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.70 : 119.30 = 78.30 : x
  2. Step 2: Convert to fraction form
    79.70/119.30 = 78.30/x
  3. Step 3: Cross multiply
    79.70x = 119.30 × 78.30
  4. Step 4: Simplify right side
    79.70x = 9,340.80
  5. Step 5: Solve for x
    x = 9,340.80/79.70
  6. Step 6: Final answer
    x = 117.21

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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.