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Finding the Fourth Proportional to 108.81, 150.21 and 87.15

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Solution

The fourth proportional to 108.81, 150.21 and 87.15 is: 120.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.81 : 150.21 = 87.15 : x
  2. Step 2: Convert to fraction form
    108.81/150.21 = 87.15/x
  3. Step 3: Cross multiply
    108.81x = 150.21 × 87.15
  4. Step 4: Simplify right side
    108.81x = 13,090.80
  5. Step 5: Solve for x
    x = 13,090.80/108.81
  6. Step 6: Final answer
    x = 120.31

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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.