Step-by-step explanation:
Sn=n/2(2a+(n-1)d)
910=n/2{2a+(n-1)d}
1820=n{2a+(n-1)d}
1820=20{2a+(20-1)d}
1820=20{2a+19d}
91=2a+19d
An=a+(n-1)d
95=a+(20-1)d
95=a+19d
91=2a+19d
---------------
4=-a
a=-4
91=2a+19d
91=2(-4)+19d
91=-8+19d
91+8=19d
99=19d
d=99/19
A=-4
We know, Volume of a Sphere = 4/3 πr³
V = 4/3 * π * (12.3)³
V = 4/3 * π * 1860.71
V = <span>2481.156π cm³
In short, Your Answer would be Option A
Hope this helps!</span>
Hey, here's a pic of it ! hope this helps !
p.s., photomath is a good app for algebraic answers with work, you should check it out (:
A.) the degrees inside the triangles are 50, 70, and 60. you know because 180-120=60
b.) you know that they are similar triangles because they have the same angle degrees.
im not sure if this is correct but i think it is :)