Will mark brainliest. =) need on two questions. see photos.

When all sides of a quadrilateral are equal (indicated by tick marks on the four sides) in length and connect the opposing vertices with a line, it will form four 90° angles. Therefore, each equation will equal 90.

10x= 90

x+y= 90

3z= 90

The measure of angles 1 and 3 can be solved as they are so:

10x= 90 ➡️ x=9

3z= 90 ➡️ z= 30

The value of x is needed to solve for the measure of angle 2 so plug in the value of x and solve:

x+y= 90

9+y= 90

y= 81

Therefore the answer is a.

Cthe residual plot for model 1 has a non random pattern and is a good fit for the data