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Finding the Fourth Proportional to 212.55, 318.51 and 90.75

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Solution

The fourth proportional to 212.55, 318.51 and 90.75 is: 135.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.55 : 318.51 = 90.75 : x
  2. Step 2: Convert to fraction form
    212.55/318.51 = 90.75/x
  3. Step 3: Cross multiply
    212.55x = 318.51 × 90.75
  4. Step 4: Simplify right side
    212.55x = 28,904.78
  5. Step 5: Solve for x
    x = 28,904.78/212.55
  6. Step 6: Final answer
    x = 135.99

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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.