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Finding the Fourth Proportional to 221.65, 305.86 and 123.40

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Solution

The fourth proportional to 221.65, 305.86 and 123.40 is: 170.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.65 : 305.86 = 123.40 : x
  2. Step 2: Convert to fraction form
    221.65/305.86 = 123.40/x
  3. Step 3: Cross multiply
    221.65x = 305.86 × 123.40
  4. Step 4: Simplify right side
    221.65x = 37,743.09
  5. Step 5: Solve for x
    x = 37,743.09/221.65
  6. Step 6: Final answer
    x = 170.28

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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.