Answer:
The correct options are 1, 2 and 4.
Step-by-step explanation:
The given triangle is an equilateral triangle. All the sides of an equilateral triangle are same. All interior angles are equal with measure 60 degree.
The distance from the center of an equilateral triangle to the midpoint of a side is known as apothem. In the given figure letter a represents the apothem.
Point D is the midpoint of BC,

Use Pythagorean theorem in triangle COD. So, option 1 is correct.





The distance can not be negative, so the length of the apothem is approximately 2.5 cm. Option 4 is correct.
The line OC bisects the angle C.



Therefore option 2 is correct.
The perimeter of an equality triangle is

Option 3 is incorrect.

Option 5 is incorrect.
Therefore options 1, 2 and 4 are correct.
Answer:
because the 1st corner and the 2nd corner is places in a straight line which the total agle is 180° so since the 1st corner has same angle as the 13th one the 14th is must be have same angle as the 2nd corner. so that the 1st corner + the 14th corner is equal as 180°
The hypothenuse is the opposite side of the right angle
so that means that in this triangle the hypotenuse is 7
Answer:
The correct option is 4.
Step-by-step explanation:
The given expression is

Simplify the given expression.


![[\because x^mx^n=x^{m+n}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20x%5Emx%5En%3Dx%5E%7Bm%2Bn%7D%5D)

Therefore correct option is 4.
It would be 20
21.3
-1.8
------
19.5 rounded would be 20