Answer:
AAS(Angle-Angle-Side) postulate states that if two angles and the non-included side one triangle are congruent to two angles and the non-included side of another triangle, then the two triangles are congruent
In triangle RAS and triangle QAT
[Angle]
[Side] [Given]
By Base Angle Theorem states that in an isosceles triangle(i.e, AST), the angles opposite the congruent sides(AS =AT) are congruent.
⇒
[By base ∠'s of isosceles triangle are equal]
By definition of supplementary angles, if two Angles are Supplementary when they add up to 180 degrees.
,
are supplementary and
,
are supplementary.
⇒
and
Two
supplementary to equal 
Since,
then, we get;
[Angle]
then, by AAS postulates,

By CPCT[Corresponding Part of Congruent Triangles are equal]
Hence Proved!
if we look on one side, we already have one measurement. 4 cm. ok, that's the measurement on that side. look to the left now. that other side is also the same length, so we take that number and multiply it be 2 to get

Wait! we're not done yet. look at the top. do you see the 3? well that's the width for the top of the rectangle. the bottom must be the same to right? so we get

add both equations and you get

The answer is 14cm! Don't forget to label. ;)
Answer:
9.9
use the special triangle formula or use cosine to find BC
In mathematics, mean average means to take the sum of all the numbers and divide the sum by the number of elements in the set.
Add up the numbers.
<span>21 + 23 + 25 + 25 + 26 + 28 + 28 + 28 + 31 + 33 = 268
Divide by the number of elements in the set. Which is 10.
268 / 10 = 26.8
So, the answer to this question is 26.8</span>
To simplify this expression would be 4x-3