A(n)=a+(n-1)d
A(40)= -1+(40-1)-4
A(40)= -1+39(-4)
A(40)= -1+(-156)
A(40)= -157
X^2 = 16
x = 4
x = -4
good luck :)
A NONA=9, nonagon has 9 sides, so it's perimeter is 7+7+7+7+7+7+7+7+7, or 63, and we know the apothem.
bearing in mind that the area of a regular polygon is
(1/2)ap a = apothem, p = perimeter
so in this case that'd be (1/2)(5)(63).
Divide the width by 2, as that is your scale.
26 / 2 = 13
The house would be 13 inches long.
The answer is B, a Rhombus
