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Finding the Fourth Proportional to 105.42, 145.19 and 90.86

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Solution

The fourth proportional to 105.42, 145.19 and 90.86 is: 125.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.42 : 145.19 = 90.86 : x
  2. Step 2: Convert to fraction form
    105.42/145.19 = 90.86/x
  3. Step 3: Cross multiply
    105.42x = 145.19 × 90.86
  4. Step 4: Simplify right side
    105.42x = 13,191.96
  5. Step 5: Solve for x
    x = 13,191.96/105.42
  6. Step 6: Final answer
    x = 125.14

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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.