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Finding the Fourth Proportional to 420.05, 629.76 and 203.57

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Solution

The fourth proportional to 420.05, 629.76 and 203.57 is: 305.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.05 : 629.76 = 203.57 : x
  2. Step 2: Convert to fraction form
    420.05/629.76 = 203.57/x
  3. Step 3: Cross multiply
    420.05x = 629.76 × 203.57
  4. Step 4: Simplify right side
    420.05x = 128,200.24
  5. Step 5: Solve for x
    x = 128,200.24/420.05
  6. Step 6: Final answer
    x = 305.20

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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.