My guess is that you're doing the Law of Cosines? You have everything you need for that except the angle theta, which is the thing you need to find. It's set up like this: (8)^2 = (10)^2 + (5)^2 -[2(10)(5)cos A] I used A instead of theta. Doing that math, you have: 64 = 100 + 25 -[ 100 cos A]; 64 = 125 - 100 cos A;
-61 = - 100 cos A; -61 / -100 = cos A; .61 = cos A. Now use your inverse function on your calculator to find cos^-1(.61) and that equals 52.4
Edges that are perpendicular to PR basically means what edges make a 90° angle with PR.
Those edges are HP , RA, TR and QP.
Hence, the answer is A, B and C.
The answer is 13 because you add.
Check the picture below.
we know B is the midpoint of AC, and we know ED is 4 units, since AD is a total of 8, then AE must also be 4 units, meaning point E is the midpoint of AD.
since E is the midpoint of AD and B is the midpoint of AC, then EB is the midsegment of the triangle, and is parallel to the base DC.
∡ABE = 60°
∡AEB = 90°
Sorry I have to go to baseball bye