From the identity,
sin^2(x)+cos^2(x)=1
then
cos(x)=sqrt(1-sin^2(x))
where sin(x) is given as 0.42.
Note that the above answer applies to 0<x<90 degrees
B. is the answer because he can just refill the 1 gallon jug to eventually measure out 3 gallons!
The answer is C <<<=====
It can't be anything else. It is not a right angle. A>90
It can't be acute because one angle is greater than 90.
It can't scalene because at least 2 of the angles (and 2 sides) are equal.
