Given:
The four expression in the options.
To find:
Which expression is equal to –1.
Solution:
In option A,

In option B,

In option C,

![[\because \sin(\pi+\theta)=-\sin \theta]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Csin%28%5Cpi%2B%5Ctheta%29%3D-%5Csin%20%5Ctheta%5D)

In option D,

![[\because \tan(\pi+\theta)=\tan \theta]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Ctan%28%5Cpi%2B%5Ctheta%29%3D%5Ctan%20%5Ctheta%5D)

Therefore, the correct option is C.
Answer:
incorrect
Step-by-step explanation:
we are finding area which is squared, or we can put it in an equation, (0.5*20)*(0.25*20) or 0.5*0.25*20^2 which equals 50 but (0.5*0.25)*20 only equals 2.5 therefor he is incorrect and the correct answer would be 20^2 or 400 times the area.
hope this helps :)