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Finding the Fourth Proportional to 212.05, 318.03 and 90.40

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Solution

The fourth proportional to 212.05, 318.03 and 90.40 is: 135.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.05 : 318.03 = 90.40 : x
  2. Step 2: Convert to fraction form
    212.05/318.03 = 90.40/x
  3. Step 3: Cross multiply
    212.05x = 318.03 × 90.40
  4. Step 4: Simplify right side
    212.05x = 28,749.91
  5. Step 5: Solve for x
    x = 28,749.91/212.05
  6. Step 6: Final answer
    x = 135.58

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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.