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Finding the Fourth Proportional to 212.20, 318.40 and 90.46

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Solution

The fourth proportional to 212.20, 318.40 and 90.46 is: 135.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.20 : 318.40 = 90.46 : x
  2. Step 2: Convert to fraction form
    212.20/318.40 = 90.46/x
  3. Step 3: Cross multiply
    212.20x = 318.40 × 90.46
  4. Step 4: Simplify right side
    212.20x = 28,802.46
  5. Step 5: Solve for x
    x = 28,802.46/212.20
  6. Step 6: Final answer
    x = 135.73

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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.