X is the domain and y is the range
There are 13 girls and 4 more students that are boys that made an A grade. Thus there are 13+4=17 students that are either girls or A students.
The probability of choosing a girl or A student is 17/30.
The sum of the measures of the angles of a triangle is 180 degrees.
An isosceles triangle has two congruent sides.
The angles opposite the congruent sides are congruent.
Just like the bottom left angle measures x, the bottom right angle also measures x.
x + x + 38 = 180
2x + 38 = 180
2x = 142
x = 71