Do you mean 5+7?
If so, that equals 12!
The answer is a+6b, if you want to know the proof please comment on this post
N=nickels
d=dimes
n+d = 30
n+18 = 30
n = 30-18
n = 12 (number of nickels)
therefore Mary has 12 nickels
Answer:
<BAC = 20°
Step-by-step explanation:
It is given in the question that all 9 triangle which are formed are congruent, which means that in all triangles, the angle which is formed at point A is same.
Which means 9 angles collectively can be written as 9 · <BAC
If we consider all the 9 triangles, we can see in the figure that it forms a semicircle.
A semicircle has a total sum of angles equal to 180°
So we can write that:
9 · <BAC = 180°
Simplify for <BAC
<BAC = 20°