The formula to find a certain number in an arithmetic sequence is an=a1+d(n-1) where an represents the nth term of the sequence, a1 is the first term of the sequence, and d is the common difference. solve for d

Step-by-step explanation:

We need to do some algebraic manipulation to the formula to get our answer [solving for d]:

Note: we will first use distributive property  a(b+c) = ab + ac

Now,

This is d's expression.

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

step-by-step explanation:

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