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Finding the Fourth Proportional to 221.64, 305.76 and 155.40

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Solution

The fourth proportional to 221.64, 305.76 and 155.40 is: 214.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.64 : 305.76 = 155.40 : x
  2. Step 2: Convert to fraction form
    221.64/305.76 = 155.40/x
  3. Step 3: Cross multiply
    221.64x = 305.76 × 155.40
  4. Step 4: Simplify right side
    221.64x = 47,515.39
  5. Step 5: Solve for x
    x = 47,515.39/221.64
  6. Step 6: Final answer
    x = 214.38

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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.