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Finding the Fourth Proportional to 212.19, 318.39 and 90.48

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Solution

The fourth proportional to 212.19, 318.39 and 90.48 is: 135.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.19 : 318.39 = 90.48 : x
  2. Step 2: Convert to fraction form
    212.19/318.39 = 90.48/x
  3. Step 3: Cross multiply
    212.19x = 318.39 × 90.48
  4. Step 4: Simplify right side
    212.19x = 28,807.93
  5. Step 5: Solve for x
    x = 28,807.93/212.19
  6. Step 6: Final answer
    x = 135.76

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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.