I can't see pictures T^T.
To find the are of a triangle, you multiply the dimensions as you would a rectangle, but divide the product by 2.
Example:
The dimensions of triangle B are 4 and 9.
4x9=36
Now divide.
36/2=18
So the area of triangle B is 18.
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hope it helps
Check the picture below
you could, also go 2/1 to the left-hand-side
M is your answer, because the tangent intersects the circle at point M.
So M is correct.
Simplies form of 3/8 is 1/4