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Finding the Fourth Proportional to 120.68, 181.63 and 90.40

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Solution

The fourth proportional to 120.68, 181.63 and 90.40 is: 136.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.68 : 181.63 = 90.40 : x
  2. Step 2: Convert to fraction form
    120.68/181.63 = 90.40/x
  3. Step 3: Cross multiply
    120.68x = 181.63 × 90.40
  4. Step 4: Simplify right side
    120.68x = 16,419.35
  5. Step 5: Solve for x
    x = 16,419.35/120.68
  6. Step 6: Final answer
    x = 136.06

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.