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Finding the Fourth Proportional to 112.82, 168.80 and 78.65

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Solution

The fourth proportional to 112.82, 168.80 and 78.65 is: 117.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.82 : 168.80 = 78.65 : x
  2. Step 2: Convert to fraction form
    112.82/168.80 = 78.65/x
  3. Step 3: Cross multiply
    112.82x = 168.80 × 78.65
  4. Step 4: Simplify right side
    112.82x = 13,275.47
  5. Step 5: Solve for x
    x = 13,275.47/112.82
  6. Step 6: Final answer
    x = 117.67

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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.