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Finding the Fourth Proportional to 213.75, 320 and 208.51

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Solution

The fourth proportional to 213.75, 320 and 208.51 is: 312.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.75 : 320 = 208.51 : x
  2. Step 2: Convert to fraction form
    213.75/320 = 208.51/x
  3. Step 3: Cross multiply
    213.75x = 320 × 208.51
  4. Step 4: Simplify right side
    213.75x = 66,723.20
  5. Step 5: Solve for x
    x = 66,723.20/213.75
  6. Step 6: Final answer
    x = 312.16

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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.