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Finding the Fourth Proportional to 212.69, 318.91 and 89.15

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Solution

The fourth proportional to 212.69, 318.91 and 89.15 is: 133.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.69 : 318.91 = 89.15 : x
  2. Step 2: Convert to fraction form
    212.69/318.91 = 89.15/x
  3. Step 3: Cross multiply
    212.69x = 318.91 × 89.15
  4. Step 4: Simplify right side
    212.69x = 28,429.01
  5. Step 5: Solve for x
    x = 28,429.01/212.69
  6. Step 6: Final answer
    x = 133.67

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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.