Hello!
For this problem we are given that quadrilateral ABCD is congruent to quadrilateral GJIH, meaning that all sides and angle measures will be equivalent to its corresponding side.
This means that to find
, we can look at quadrilateral GJIH's corresponding side to quadrilateral ABCD's side AD, which is side GH, which has a value of 9.
This means that 9 should also be the side length of side AD, which we're given a value of
.

Solve.

Hope this helps!
EDIT:
Order of operations doesn't matter in addition. So you can add them in any order.
The students in math class use square tiles to make arrays. If they
- use 8 (8=1·2·2·2) tiles, then they can form arrays of the length in 1 tile, 2 tiles, 4 tiles and 8 tiles;
- use 9 (9=1·3·3) tiles, they can form arrays of the length in 1 tile, 3 tiles and 9 tiles (one array less).
So, you can conclude that Celia is correct.
The answer is -1/4 I’m in 11th grade trust me
These two have different denominators, so you find the least common multiple. This problem goes to be 2/8+5/8, which equals 7/8。