Answer:
Reinforcement
x - 81 = 321
adding 81 on both sides
x-81+81= 321+81
x= 402
I don't have any sense lol but ummmm Sunday I'm guessing.
Step-by-step explanation:
B
30
7 * 3 = 21
3 * 3 = 9 which covers for both triangles
each triangle is half of a square. so each triangle is 4.5 sq. units
add 21 with 9
21 + 9 = 30