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Finding the Fourth Proportional to 405.85, 608.79 and 145.78

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Solution

The fourth proportional to 405.85, 608.79 and 145.78 is: 218.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.85 : 608.79 = 145.78 : x
  2. Step 2: Convert to fraction form
    405.85/608.79 = 145.78/x
  3. Step 3: Cross multiply
    405.85x = 608.79 × 145.78
  4. Step 4: Simplify right side
    405.85x = 88,749.41
  5. Step 5: Solve for x
    x = 88,749.41/405.85
  6. Step 6: Final answer
    x = 218.68

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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.