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Finding the Fourth Proportional to 212.56, 318.68 and 90.88

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Solution

The fourth proportional to 212.56, 318.68 and 90.88 is: 136.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.56 : 318.68 = 90.88 : x
  2. Step 2: Convert to fraction form
    212.56/318.68 = 90.88/x
  3. Step 3: Cross multiply
    212.56x = 318.68 × 90.88
  4. Step 4: Simplify right side
    212.56x = 28,961.64
  5. Step 5: Solve for x
    x = 28,961.64/212.56
  6. Step 6: Final answer
    x = 136.25

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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.