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Finding the Fourth Proportional to 212.36, 318.63 and 90.71

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Solution

The fourth proportional to 212.36, 318.63 and 90.71 is: 136.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.36 : 318.63 = 90.71 : x
  2. Step 2: Convert to fraction form
    212.36/318.63 = 90.71/x
  3. Step 3: Cross multiply
    212.36x = 318.63 × 90.71
  4. Step 4: Simplify right side
    212.36x = 28,902.93
  5. Step 5: Solve for x
    x = 28,902.93/212.36
  6. Step 6: Final answer
    x = 136.10

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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.