pls help me answer 10, 11, and 12 thx in advance

I'll help with 10,
A=b×h÷2 is your equation so I would substitute in the six and eight next.
The base is 6 and the height is 8 so 6×8÷2=A
Then I would do 6×8=48, 48÷2 is 24.
The area is 24 cm squared.