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Finding the Fourth Proportional to 419.94, 629.90 and 111.78

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Solution

The fourth proportional to 419.94, 629.90 and 111.78 is: 167.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.94 : 629.90 = 111.78 : x
  2. Step 2: Convert to fraction form
    419.94/629.90 = 111.78/x
  3. Step 3: Cross multiply
    419.94x = 629.90 × 111.78
  4. Step 4: Simplify right side
    419.94x = 70,412.08
  5. Step 5: Solve for x
    x = 70,412.08/419.94
  6. Step 6: Final answer
    x = 167.67

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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.