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Finding the Fourth Proportional to 210.78, 315.95 and 80.75

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Solution

The fourth proportional to 210.78, 315.95 and 80.75 is: 121.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.78 : 315.95 = 80.75 : x
  2. Step 2: Convert to fraction form
    210.78/315.95 = 80.75/x
  3. Step 3: Cross multiply
    210.78x = 315.95 × 80.75
  4. Step 4: Simplify right side
    210.78x = 25,511.66
  5. Step 5: Solve for x
    x = 25,511.66/210.78
  6. Step 6: Final answer
    x = 121.03

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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.