D is on side AC of Triangle ABC. We know [ABC] = 120, AD = 8, DC = 4. What is [ABD]?

D is on side AC of Triangle ABC. We know [ABC] = 120, AD = 8, DC = 4. What is [ABD]?

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Let BD be x

 

8x + 4x = 240

 

x = 20

 

[ABD] = 8x / 2 = 80 u²