Gareth believes that if he flips a coin 820 times, it will land heads up exactly 410 times. What would you tell Gareth about his prediction?

I would tell Gareth that he is wrong, and right.

Step-by-step explanation:

When dealing with a coin flip, there will be a 50/50 chance for it to land heads or tails every time, but this doesn't mean that it will land like that every time either. It could land 819 times heads and 1 times tails, but unless something is affecting it each time the probability won't change.

no not all of them.

step-by-step explanation:

some of them have a square base.

proofs involving isosceles triangles often require special consideration because an isosceles triangle has several distinct properties that do not apply to normal triangles.(more about triangle types) therefore, when you are trying to prove that two triangles are congruent, and one or both triangles, are isosceles you have a few theorems that you can use to make your life easier.

step-by-step explanation:

an isosceles triangle has two congruent sides and two congruent angles. the congruent angles are called the base angles and the other angle is known as the vertex angle. ∠bac and ∠bca are the base angles of the triangle picture on the left. the vertex angle is ∠abc