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Finding the Fourth Proportional to 212.17, 318.09 and 90.53

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Solution

The fourth proportional to 212.17, 318.09 and 90.53 is: 135.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.17 : 318.09 = 90.53 : x
  2. Step 2: Convert to fraction form
    212.17/318.09 = 90.53/x
  3. Step 3: Cross multiply
    212.17x = 318.09 × 90.53
  4. Step 4: Simplify right side
    212.17x = 28,796.69
  5. Step 5: Solve for x
    x = 28,796.69/212.17
  6. Step 6: Final answer
    x = 135.72

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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.