Answer:
DE = 20 units
Step-by-step explanation:
GIVEN :-
- D & E are the mid-points of AB & BC respectively.
- DE = 4x + 4
- AC = x + 36
TO FIND :-
FACTS TO KNOW BEFORE SOLVING :-
- The midsegment of a triangle is a line constructed by connecting the midpoints of any two sides of the triangle.
- The Triangle Midsegment Theorem tells us that a midsegment is one-half the length of the third side (the base), and it is also parallel to the base.
PROCEDURE :-
According to Triangle Midsegment Theorem ,
[tex]DE = \frac{AC}{2}[/tex]
[tex]=> 4x + 4 = \frac{x + 36}{2}[/tex]
Multiplying 2 on both the sides ,
[tex]=> 2(4x + 4) = x + 36[/tex]
[tex]=> 8x + 8 = x + 36[/tex]
[tex]=> 8x - x = 36 - 8[/tex]
[tex]=> 7x = 28[/tex]
[tex]=> x = \frac{28}{7} = 4[/tex]
∴ DE = 4×4 + 4 = 20 units