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Finding the Fourth Proportional to 212.31, 318.50 and 90.57

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Solution

The fourth proportional to 212.31, 318.50 and 90.57 is: 135.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.31 : 318.50 = 90.57 : x
  2. Step 2: Convert to fraction form
    212.31/318.50 = 90.57/x
  3. Step 3: Cross multiply
    212.31x = 318.50 × 90.57
  4. Step 4: Simplify right side
    212.31x = 28,844.95
  5. Step 5: Solve for x
    x = 28,844.95/212.31
  6. Step 6: Final answer
    x = 135.87

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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.