CPhill

The angle supplementary to 130° = 50°

So...the missing angle in the top triangle = 180 - 45 - 50 = 85°

And the angle supplemental to this is 95°

So....x = 180 - 95 - 30  =  180 - 125  =  55°

Ah....thanks, Tetre.....I always forget that they want the perimeter of the whole sector....not just the "curved" part

Best Answer !!!

Semi-circle perimeter =   pi * radius   =

pi * 3 =

3 pi  cm

EDIT....see tertre's answer below.....mine is flawed!!!

Area of a semi-circle  =  (1/2)pi *(radius)^2.....so ...

(1/2) (3.142) * (8.2)^2 =  

105.6 cm^2

First term  1 = r + r^2   →  r = 1 - r^2   →   r^2 = 1 - r

Sum  =     1 / (1 - r )   =      1  / [ 1 - (1 - r^2) ]      =   1 / r^2    

r - s  =

r - 1/r^2  =

[ r^3 - 1 ] / [  1 - r ] =

- [ 1 - r^3 ] / [ 1 - r ] =

- [ 1 - r ] [ 1 + r + r^2 ] / [ 1 - r ]  =

- [ 1 + r + r^2 ] =

- [ 1 + (r + r^2 ) ] =

- [ 1 + 1 ] =

-2

Looks good, GM !!!!!

We have a    parabola that opens upward......the vertex is (6, 1)

The y value of 1 is the minimum value on the graph......so....the range is   [ 1, infinity )

I'm going to guess that you meant

x^2 - x =  30          subtract 30 from both sides

x^2 - x -30 =  0      factor

(x - 6) ( x + 5) = 0

Set both factors to 0  and solve for x and we get that    x = 6    or x = -5

Exactly the same

Post your answers if you want to and I'll check...