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Finding the Fourth Proportional to 427.12, 640.80 and 153.20

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Solution

The fourth proportional to 427.12, 640.80 and 153.20 is: 229.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.12 : 640.80 = 153.20 : x
  2. Step 2: Convert to fraction form
    427.12/640.80 = 153.20/x
  3. Step 3: Cross multiply
    427.12x = 640.80 × 153.20
  4. Step 4: Simplify right side
    427.12x = 98,170.56
  5. Step 5: Solve for x
    x = 98,170.56/427.12
  6. Step 6: Final answer
    x = 229.84

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.