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Finding the Fourth Proportional to 305.15, 421.25 and 216.81

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Solution

The fourth proportional to 305.15, 421.25 and 216.81 is: 299.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.15 : 421.25 = 216.81 : x
  2. Step 2: Convert to fraction form
    305.15/421.25 = 216.81/x
  3. Step 3: Cross multiply
    305.15x = 421.25 × 216.81
  4. Step 4: Simplify right side
    305.15x = 91,330.13
  5. Step 5: Solve for x
    x = 91,330.13/305.15
  6. Step 6: Final answer
    x = 299.30

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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.