Answer:
The length side of the triangle is 
Step-by-step explanation:
we know that
The equilateral triangle has three equal sides and three equal internal angles of measure of 60 degrees each.
Let
b------> the length side of the equilateral triangle
Applying Pythagoras theorem

Answer: its option "b"
Pentagon;not regular
Step-by-step explanation:
The polygon has 5 sides but all the sides are not equal
hence, it is an irregular pentagon
Hope this helped you!!
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Answer:
D
Step-by-step explanation:
hope this helps
Step 1. Identify the variable.
Step 2. Write an algebraic equation.
Step 3. Solve the equation.
Step 4. Answer the equation.
Step 5. Check answer.
Hope this helps...?
If you add that together you get 28