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Finding the Fourth Proportional to 221.40, 305.44 and 128.08

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Solution

The fourth proportional to 221.40, 305.44 and 128.08 is: 176.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.40 : 305.44 = 128.08 : x
  2. Step 2: Convert to fraction form
    221.40/305.44 = 128.08/x
  3. Step 3: Cross multiply
    221.40x = 305.44 × 128.08
  4. Step 4: Simplify right side
    221.40x = 39,120.76
  5. Step 5: Solve for x
    x = 39,120.76/221.40
  6. Step 6: Final answer
    x = 176.70

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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.