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Finding the Fourth Proportional to 305.64, 421.76 and 189.20

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Solution

The fourth proportional to 305.64, 421.76 and 189.20 is: 261.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.64 : 421.76 = 189.20 : x
  2. Step 2: Convert to fraction form
    305.64/421.76 = 189.20/x
  3. Step 3: Cross multiply
    305.64x = 421.76 × 189.20
  4. Step 4: Simplify right side
    305.64x = 79,796.99
  5. Step 5: Solve for x
    x = 79,796.99/305.64
  6. Step 6: Final answer
    x = 261.08

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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.