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Finding the Fourth Proportional to 210.45, 315.69 and 80.47

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Solution

The fourth proportional to 210.45, 315.69 and 80.47 is: 120.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.45 : 315.69 = 80.47 : x
  2. Step 2: Convert to fraction form
    210.45/315.69 = 80.47/x
  3. Step 3: Cross multiply
    210.45x = 315.69 × 80.47
  4. Step 4: Simplify right side
    210.45x = 25,403.57
  5. Step 5: Solve for x
    x = 25,403.57/210.45
  6. Step 6: Final answer
    x = 120.71

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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.