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Finding the Fourth Proportional to 251.28, 378.72 and 215.64

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Solution

The fourth proportional to 251.28, 378.72 and 215.64 is: 325.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    251.28 : 378.72 = 215.64 : x
  2. Step 2: Convert to fraction form
    251.28/378.72 = 215.64/x
  3. Step 3: Cross multiply
    251.28x = 378.72 × 215.64
  4. Step 4: Simplify right side
    251.28x = 81,667.18
  5. Step 5: Solve for x
    x = 81,667.18/251.28
  6. Step 6: Final answer
    x = 325.00

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.