Me do question 21, 22 and 23. i am in 6th grade.

Question 21: 24 minutes

x =

x = 24

Question 22: 20 centimeters

x = one side of the square

x² = 25

x = 5

4x = perimeter

4(5) = perimeter

20 = perimeter

Question 23: 17 sides

Hexagon = 6 sides

Octagon = 8 sides

Triangle = 3 sides

Total amount of sides = 6 + 8 + 3

Total amount of sides = 17

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2

8+10

step-by-step explanation:

you multiply 4 by 2 and 5 by 2