If jk lm , which statement is true ?

The answer to this question would be: B. JK and LM meet at a right angle.

The reversed T symbol in this question means "perpendicular". That means the JK and LM line have 90-degree angle difference. A straight angle is 180 degree and right angle mean 90 degrees.
A perpendicular line should be in the same plane and intersect each other.

You can find the area of a rectangle by multiplying the length and height. so multiply 1/2*7/4(which is the simpler version of 1 3/4) and you get 7/8 as your answer.