Answer:
right triangle
Step-by-step explanation:
because 15 would be the base so 11 and 12 would be the sides and fot the triangle to be acute or obtuse the total of the sides (11+12) has to be lass than the base (15), but it is more 23 so it has to be a right triangle.
here you go..............
b.) cos((π/2)-Ф)=-3/5 is true because :
cos((π/2)-Ф)= sin(Ф)
1.8
is the median