What would X= I don’t understand this

so, the 3 angles in a triangle add up to 180.

I'm going to assume the top angles are equal.

therefore, the top angles are (180- 40)/2

180-40=140 140/2= 70.

so, each of the top angles is 70

we also know the total of angles adding up to a straight line is 180- so x would be whatever is left after 70 is removed from 180.

180-70= 110

x=110 degrees

to find the perimeter of the rectangle this is the expression:

x-9+x-9+3x-4+3x-4=138

if we simplify it:

8x-26=138

remember, 138 is what it all adds up to

the length is 11.5cm

the width is 57.5cm

the area is 661.25cm^2

the answers might not be correct use at own risk