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Finding the Fourth Proportional to 369.12, 509.40 and 221.72

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Solution

The fourth proportional to 369.12, 509.40 and 221.72 is: 305.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    369.12 : 509.40 = 221.72 : x
  2. Step 2: Convert to fraction form
    369.12/509.40 = 221.72/x
  3. Step 3: Cross multiply
    369.12x = 509.40 × 221.72
  4. Step 4: Simplify right side
    369.12x = 112,944.17
  5. Step 5: Solve for x
    x = 112,944.17/369.12
  6. Step 6: Final answer
    x = 305.98

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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.