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Finding the Fourth Proportional to 305.40, 421.18 and 216.96

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Solution

The fourth proportional to 305.40, 421.18 and 216.96 is: 299.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.40 : 421.18 = 216.96 : x
  2. Step 2: Convert to fraction form
    305.40/421.18 = 216.96/x
  3. Step 3: Cross multiply
    305.40x = 421.18 × 216.96
  4. Step 4: Simplify right side
    305.40x = 91,379.21
  5. Step 5: Solve for x
    x = 91,379.21/305.40
  6. Step 6: Final answer
    x = 299.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.