I- GUESS WHO NEEDS HELP AGAIN...
I don't wanna fail math a

C

Step-by-step explanation:

Follow Pythagorean Theorem. a^2 + b^2 = c^2

We know b and c:

a^2 + 12^2 = 13^2

a^2 + 144 = 169

a^2 = 25

a = √25

a = 5

The answer is C because we know side a = 5

Give this branliest

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

< 6 cm to > 26 cm i believe

step-by-step explanation: