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Finding the Fourth Proportional to 427.79, 642.12 and 208.57

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Solution

The fourth proportional to 427.79, 642.12 and 208.57 is: 313.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.79 : 642.12 = 208.57 : x
  2. Step 2: Convert to fraction form
    427.79/642.12 = 208.57/x
  3. Step 3: Cross multiply
    427.79x = 642.12 × 208.57
  4. Step 4: Simplify right side
    427.79x = 133,926.97
  5. Step 5: Solve for x
    x = 133,926.97/427.79
  6. Step 6: Final answer
    x = 313.07

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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.