Step-by-step explanation:

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!
Answer:
1 2/3 = 1 8/12
Step-by-step explanation:
2/3 * 4/4 because 3*4= 12 is 8/12 hope this helps :)
Answer:
x = - 8, y = 2
Step-by-step explanation:

Suppose x quarts of the 50% solution
0.5x+0.2*20=0.4(x+20)
0.5x+4=0.4x+8
0.1x=4
x=40