Answer:
No, if fit means that the sides of the book case need to be flush with the wall, which means that the sides of the bookcase are touching the wall and the bookcase fits perfectly in that spot
Step-by-step explanation:
A square room will have corners that meause 90°, so we need to see if any of the vertices of the bookcase measure 90°. All right triangles have a 90° in them, so we can use Pythagorean Theorem to solve this.
Pythagorean Theorem is a² + b² = c², where a and b are the legs, and c is the hypotenuse. Since the hypotenuse is always the longest side, for our bookshelf, 10 and 12 are the legs, and 18 would be the hypotenuse if it is a right triangle. Plug the values in to see if the equation is true or false
10² + 12² = 18²
100 + 144 = 324
244 ≠ 324 so the bookcase does not form a right angle, and won't fit in the corner of the room