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Finding the Fourth Proportional to 153.50, 211.84 and 86.21

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Solution

The fourth proportional to 153.50, 211.84 and 86.21 is: 118.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.50 : 211.84 = 86.21 : x
  2. Step 2: Convert to fraction form
    153.50/211.84 = 86.21/x
  3. Step 3: Cross multiply
    153.50x = 211.84 × 86.21
  4. Step 4: Simplify right side
    153.50x = 18,261.88
  5. Step 5: Solve for x
    x = 18,261.88/153.50
  6. Step 6: Final answer
    x = 118.97

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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.