What does it say 3.5 or 3.50
Answer:
The amount of steel used = 94.38 
Step-by-step explanation:
Height of the tank = 4.5 m.
Diameter of the tank = 4.2 m.
But,
radius = 
= 
radius = 2.1 m
Total surface area of a cylinder = 2
rh + 2

= 2
r(r + h)
= 2 x
x 2.1 (2.1 + 4.5)
= 44 x 0.3 (6.6)
= 87.12
Total surface area of a cylinder = 87.12 
Since
of the steel was wasted, then;
x 87.12 = 7.26 
Actual area of steel sheet used = 87.12 + 7.26
= 94.38 
Thus, 94.38
of steel was used in making the tank.
What are the angles?
if all of them are below 90 degrees, it is acute.
if one angle is 90 degress, it is right
if one angle is more than 90 degrees, it is obtuse
It's A ...cos (90- theta) = sin theta
so A