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Finding the Fourth Proportional to 305.12, 421.28 and 188.72

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Solution

The fourth proportional to 305.12, 421.28 and 188.72 is: 260.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.12 : 421.28 = 188.72 : x
  2. Step 2: Convert to fraction form
    305.12/421.28 = 188.72/x
  3. Step 3: Cross multiply
    305.12x = 421.28 × 188.72
  4. Step 4: Simplify right side
    305.12x = 79,503.96
  5. Step 5: Solve for x
    x = 79,503.96/305.12
  6. Step 6: Final answer
    x = 260.57

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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.