Answer:
Solution given:
b=9 base side of isosceles triangle
a=
We will use distribution
we will multiply 6 to each variable and number in the parenthesis.
6 times x plus 6 times 4
which is 6x +24
Answer:

Step-by-step explanation:
we know that
An exterior angle of a triangle is equal to the sum of the opposite interior angles.
see the attached figure to better understand the problem
so
∠DEF=∠ECD+∠CDE
substitute the given values

solve for x
Combine like terms

Group terms



Find the measure of angle CDE

substitute the value of x

This is really obvious but the answer is 4 feet.