Answer :
give the known angle (90) a pronumeral of r.
give the second angle (the one with all the subtraction) a pronumeral or x.
give the third angle the pronumeral of y
x = 7y - 6
90 + x + y = 180
90 + 7y - 6 + y = 180
90 + 8y - 6 = 180
90 + 8y =186
8y = 96
y = 12. the third angle is 12
so 12 + 90 = 102
the second angle must equal 88 to make it to 180
give the second angle (the one with all the subtraction) a pronumeral or x.
give the third angle the pronumeral of y
x = 7y - 6
90 + x + y = 180
90 + 7y - 6 + y = 180
90 + 8y - 6 = 180
90 + 8y =186
8y = 96
y = 12. the third angle is 12
so 12 + 90 = 102
the second angle must equal 88 to make it to 180