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Finding the Fourth Proportional to 212.80, 319.19 and 84.55

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Solution

The fourth proportional to 212.80, 319.19 and 84.55 is: 126.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.80 : 319.19 = 84.55 : x
  2. Step 2: Convert to fraction form
    212.80/319.19 = 84.55/x
  3. Step 3: Cross multiply
    212.80x = 319.19 × 84.55
  4. Step 4: Simplify right side
    212.80x = 26,987.51
  5. Step 5: Solve for x
    x = 26,987.51/212.80
  6. Step 6: Final answer
    x = 126.82

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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.