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Finding the Fourth Proportional to 305.40, 421.20 and 218.16

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Solution

The fourth proportional to 305.40, 421.20 and 218.16 is: 300.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.40 : 421.20 = 218.16 : x
  2. Step 2: Convert to fraction form
    305.40/421.20 = 218.16/x
  3. Step 3: Cross multiply
    305.40x = 421.20 × 218.16
  4. Step 4: Simplify right side
    305.40x = 91,888.99
  5. Step 5: Solve for x
    x = 91,888.99/305.40
  6. Step 6: Final answer
    x = 300.88

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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.