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Finding the Fourth Proportional to 212.07, 318.29 and 90.43

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Solution

The fourth proportional to 212.07, 318.29 and 90.43 is: 135.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.07 : 318.29 = 90.43 : x
  2. Step 2: Convert to fraction form
    212.07/318.29 = 90.43/x
  3. Step 3: Cross multiply
    212.07x = 318.29 × 90.43
  4. Step 4: Simplify right side
    212.07x = 28,781.72
  5. Step 5: Solve for x
    x = 28,781.72/212.07
  6. Step 6: Final answer
    x = 135.72

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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.