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Finding the Fourth Proportional to 212.10, 318.12 and 90.30

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Solution

The fourth proportional to 212.10, 318.12 and 90.30 is: 135.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.10 : 318.12 = 90.30 : x
  2. Step 2: Convert to fraction form
    212.10/318.12 = 90.30/x
  3. Step 3: Cross multiply
    212.10x = 318.12 × 90.30
  4. Step 4: Simplify right side
    212.10x = 28,726.24
  5. Step 5: Solve for x
    x = 28,726.24/212.10
  6. Step 6: Final answer
    x = 135.44

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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.