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Finding the Fourth Proportional to 155.72, 214.89 and 86.72

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Solution

The fourth proportional to 155.72, 214.89 and 86.72 is: 119.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.72 : 214.89 = 86.72 : x
  2. Step 2: Convert to fraction form
    155.72/214.89 = 86.72/x
  3. Step 3: Cross multiply
    155.72x = 214.89 × 86.72
  4. Step 4: Simplify right side
    155.72x = 18,635.26
  5. Step 5: Solve for x
    x = 18,635.26/155.72
  6. Step 6: Final answer
    x = 119.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.