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Finding the Fourth Proportional to 126.81, 190.35 and 78.75

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Solution

The fourth proportional to 126.81, 190.35 and 78.75 is: 118.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.81 : 190.35 = 78.75 : x
  2. Step 2: Convert to fraction form
    126.81/190.35 = 78.75/x
  3. Step 3: Cross multiply
    126.81x = 190.35 × 78.75
  4. Step 4: Simplify right side
    126.81x = 14,990.06
  5. Step 5: Solve for x
    x = 14,990.06/126.81
  6. Step 6: Final answer
    x = 118.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.