-625
use long multiplication to evaluate .
2y+20=100
2y=80
y=40
The explanation for this would because because the two base angles of an isosceles triangle are equal so since the both equal to 40 degrees, in total would be 80 degrees.
Since the total degrees of a triangle is 180 and you know the base angles make up for 80 percent you subtract that from the total of the angle your trying to find, which is 2y+20.
Answer:
The area of the triangle is 
Step-by-step explanation:
Given:
Coordinates D (0, 0), E (1, 1)
Angle ∠DEF = 60°
△DEF is a Right triangle
To Find:
The area of the triangle
Solution:
The area of the triangle is = 
Here the base is Distance between D and E
calculation the distance using the distance formula, we get
DE = 
DE =
DE = 
DE = 
Base = 
Height is DF
DF =
DF = 
DF = 
Now, the area of the triangle is
= 
=
=
=
The answer in 27 $$$$$$$$$$$$$$$$$$$$$$$$