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Finding the Fourth Proportional to 212.92, 319.26 and 91.15

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Solution

The fourth proportional to 212.92, 319.26 and 91.15 is: 136.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.92 : 319.26 = 91.15 : x
  2. Step 2: Convert to fraction form
    212.92/319.26 = 91.15/x
  3. Step 3: Cross multiply
    212.92x = 319.26 × 91.15
  4. Step 4: Simplify right side
    212.92x = 29,100.55
  5. Step 5: Solve for x
    x = 29,100.55/212.92
  6. Step 6: Final answer
    x = 136.67

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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.