Enter the number of the following expressions that are equal to $(5+61)+11+19$.(a) $(61+5)+19+11$(b) $5+(61+11)+19$(c) $11+5+61+19$(d) $5+16+(11+91)$(e) $(61+5+11+19)$(f) $11+(5+61+19)$

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Thales was an ancient philosopher familiar with similar triangles. one story about him says that he found the height of a pyramid by measuring its shadow and his own shadow at the same time. if the person is 5-ft tall, what is the height of the pyramid in the drawing?

Are triangles the congruent? write the congruency statement.what is the congruency that proves they are congruent? what is the perimeter of ∆pqr?