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Finding the Fourth Proportional to 427.96, 641.78 and 208.45

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Solution

The fourth proportional to 427.96, 641.78 and 208.45 is: 312.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.96 : 641.78 = 208.45 : x
  2. Step 2: Convert to fraction form
    427.96/641.78 = 208.45/x
  3. Step 3: Cross multiply
    427.96x = 641.78 × 208.45
  4. Step 4: Simplify right side
    427.96x = 133,779.04
  5. Step 5: Solve for x
    x = 133,779.04/427.96
  6. Step 6: Final answer
    x = 312.60

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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.