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Finding the Fourth Proportional to 212.08, 317.97 and 90.31

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Solution

The fourth proportional to 212.08, 317.97 and 90.31 is: 135.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.08 : 317.97 = 90.31 : x
  2. Step 2: Convert to fraction form
    212.08/317.97 = 90.31/x
  3. Step 3: Cross multiply
    212.08x = 317.97 × 90.31
  4. Step 4: Simplify right side
    212.08x = 28,715.87
  5. Step 5: Solve for x
    x = 28,715.87/212.08
  6. Step 6: Final answer
    x = 135.40

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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.