Question

1. Two angles are complementary. The smaller angle is 35° less than the larger angle. What is the measure of the larger angle?
A) 27.5°
B) 62.5°
C) 125°

2. A right circular cylinder has a base diameter of 12 meters and a height of 16 meters. What is the approximate total lateral surface area of the cylinder?
A) 602.9 m²
B) 1507.2 m²
C) 2034.7 m²

Answer 1

For number 1, the answer is B 62.5° but I don't know how you got that number:(
and for number 2, does this mean that I have to add the lateral area and the surface area of the cylinder?

Answer 2

complementary angles add upto 90 degrees
so, if smaller angle is x, larger angle is x+35
right ?

Answer 3

then just add them and equate to 90.

Answer 4

@hartnn umm..ok I am totally blacked out..so, x+35 how would I solve for this..??

Answer 5

smaller angle =x, larger angle =x+35
sum = 90 = x+x+35
so, can u find x from the above equation ?

Answer 6

@hartnn oh~~!! yupp!! got it! it's
90=x+x+35
90=2x+35
55=2x
27.5=x

so, the larger angle= x+35
27.5+35 = 62.5

right?!

Answer 7

good work! correct :)

Answer 8

@hartnn thank you!!! and if you can, can you help me out with the second question please?

Answer 9

sure, only lateral surface area is asked.
know the formula ?

Answer 10

For the surface area, I know it's S.A.=2(PI)r*h+2(PI)r^2
and the lateral area...I'm not sure..

Answer 11

total surface is made of 2 base areas, 2pi r^2
and lateral surface are 2pi r *h

Answer 12

@hartnn is the "surface area" and the "total surface area" the same thing?

Answer 13

yes.

Answer 14

but theres the word lateral, so u need to use 2pi r*h

Answer 15

@hartnn ah ok give me a sec, i'll solve for the surface area and the lateral area=)

Answer 16

@hartnn ok so the Surface area is
S.A.= 2(pi)r^2
S.A.= 2(pi)6^2
S.A.= 72 (pi) = 226.1946711

the lateral area is
L.A.=2(pi)r*h
L.A.=2(pi)6*16
L.A.=192(pi)=603.1857895

Answer 17

LA was asked and its 603 is correct.
Also , total surface area is always > lateral.
what you calculated as 2pi r^2 was the total base area

Answer 18

and SA =base area + lateral area.

Answer 19

S.A.=2(PI)r*h+2(PI)r^2

Answer 20

oh oh ok so, the surface area is 226.1946711+603.1857895 =829.3804606

Answer 21

yes, correct.

Answer 22

thats total surface area.

Answer 23

ah so now should I add 829.3804606 and 603.1857895 together?

Answer 24

why ?

Answer 25

only lateral area is asked and its 603

Answer 26

@hartnn oh I thought that (total "lateral" "surface" area of the cylinder) meant that I had to add the lateral area and surface area.

Answer 27

@hartnn so they are just asking about the lateral area? then the answer would be A) 602.9 m² ?

Answer 28

yes.

Answer 29

@hartnn Oh~ ok I see:) thank you soooo much!! you helped me a lot!!

Answer 30

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