So we know that surface area is top circle +bottom circle+ (circumfurence times height so) 2(π(radius)^2)+(height(2π(r))) so fill in the blanks
it's kind of hard to see but πr means pi times radius (r)
2πr^2+((4.2)(2)(π)(r))=628.3
factor out the 2 so the equation would mean
2((πr^2)+(4.2πr))=628.3
divide both sides by 2
πr^2+4.2πr=314.15
what's interesting is that the first few digits of pi are 3.1415 so we aproximate pi as 3.14 and divide both sides by 3.1415
r^2+4.2r=100
subtract 100 from both sides
r^2+4.2r-100=0
factor
(x-8.11812)(x+12.3181)=0
so (if xy=0 then x or/and y must be 0 so)we set them to 0 so
x-8.11812=0
x=8.11812
second one
x+12.3181=0
x=-12.3181
since radii (or any legnth) cannot be negative, we can cross this solution out so
radius=8.11812
In an observational study, only one group is studied, and in an expirement, two groups are studied.
Answer:
here down is the answer
(2y/5y)^3+4y^2+6y
8y^3/125y^3 +16y^2+6y
8/125+16y^2+6y
8/125+16y^2+6y=0
16y^2+6y+8/125=0
it is in the form of quadratic equation
formula :
x=(-b+-square root of b^2-4ac) /2a
here a=16,b=6&c=8/125
x=(-b+-square root of b^2-4ac)/2a
x=(-6+-square root of 36-4.09)/2a here 4.09 came by calculation
x=(-6+-31.91)/2
so
x=(-6+31.91)/2 first (+);
x=25.91/2
x=12.955;
x=(-6-31.91)/2 then(-);
x=-37.91/2
x=-18.955 ;
ans is = 12.955&-18.955;
