[i absolutely don't get this, sterling silver is an alloy of 92.5% sliver and 7.5% copper by weight. you have 15 ounces of 800 grade silver which is 80% silver and 20% copper. how much pure silver should you add to the 800 grade to make sterling silver?

If is the amount of pure silver you add to the alloy, then the new alloy will have a total weight of oz. You want 92.5% of this alloy to be silver, so that the amount of silver in the new alloy is .

80% of the starting 15 oz alloy was silver; this comes out to 12 oz. To this amount we are adding . So

and solving this tells you that you need to add oz of silver to get the sterling silver alloy.

eve and marks ratios are equivalent

step-by-step explanation:

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