PLSSS HELP FIRST ONE TO ANSWER WILL GET BRAINLIEST PLSS HELP

What is the area of the triangle 10 13 12

Ahypothesis is: a the average squared deviations about the mean of a distribution of values b) an empirically testable statement that is an unproven supposition developed in order to explain phenomena a statement that asserts the status quo; that is, any change from what has been c) thought to be true is due to random sampling order da statement that is the opposite of the null hypothesis e) the error made by rejecting the null hypothesis when it is true

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)