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Finding the Fourth Proportional to 108.75, 149.94 and 90.21

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Solution

The fourth proportional to 108.75, 149.94 and 90.21 is: 124.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    108.75 : 149.94 = 90.21 : x
  2. Step 2: Convert to fraction form
    108.75/149.94 = 90.21/x
  3. Step 3: Cross multiply
    108.75x = 149.94 × 90.21
  4. Step 4: Simplify right side
    108.75x = 13,526.09
  5. Step 5: Solve for x
    x = 13,526.09/108.75
  6. Step 6: Final answer
    x = 124.38

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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.