The product of the slopes of two non-vertical perpendicular lines is always -1. it is not possible for two perpendicular lines to both have a positive slope because the product of two positives is positive. so for the product of the slopes to be -1, one of the slopes must be positive and the other negative.

is this true or false?

It is true.

Step-by-step explanation:

For example:

If the slope of a line "A" is 3/4 and it is perpendicular to a line "B", then the slope of the line B must be -4/3, because the slope of perpendicular lines are opposite reciprocal.

If you multiply this slopes, you obtain:

Therefore, keeping the explanation above on mind, the answer is: True.

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.