An isosceles triangle has a base whose length is 14 centimeters and whose base angle each measure 68

I guess you want to find the lenght of the sides and the other angle, so let's do that:

We know that the base has a length of 14 cm.

The two base angles are 68°

First, we can find the other angle knowing that the sum of all interior angles of a triangle must add up to 180°.

2*68° + X = 180°

X = 180° - 2*68° = 44°

Now let's find the length of the sides (that is the same for both sides, as we have an isosceles triangle.

For this we can draw a line for the middle of the base that goes through the top vertex, creating in this way a triangle rectangle.

We know that one of the cathetus will have half of the length of the base, this is 7cm.

the adjacent angle to this cathetus is 68°, now we want to find the hypotenuse of this triangle, we can use the relation:

Cos(A) = adjacent cathetus/hypotenuse:

Cos(68°) = 7cm/H

H = 7cm/cos(68) = 18.7cm

this hypotenuse is equal to the side length of our isosceles triangle, so now we have it fully determined.

assuming you mean addition: addition and subtraction are reverse operations.

step-by-step explanation:

it would open into a square depending on the type of envelope i’m not sure about the second part