Lines are perpendicular if the slope of one is the negative reciprocal of the other. In this case the slopes are -8/3 and 8/3, so while negative they are not reciprocal. So no, the two lines intersect but are not perpendicular.
Answer:
Step-by-step explanation:
Variance is the sum of squares of all items x from mean. i.e
Variance = 
Being the sum of squares variance can never be negative irrespective of mean being negative.
Std deviation is the square root of variances. This will thus be less than variance if variance >1 other wise std deviation will be bigger than variance.
Hence option d is right.
The answer will most likely be 56 degrees try that it should be the answer!
Answer:
287 books
Step-by-step explanation
there was already 239 books. when the problem mentoins that Mary ADDS MORE books to the shelf, the operation is addition.
239+48=287
Right triangle
hope this helped