Hi. i need help with this question.

Workings Please.

1. A 210° sector of a circle of radius 10cm is used to make a cone. Find the radius of the base of the cone and it's height.

 radius = 5.83 cm     height = 8.12 cm

Step-by-step explanation:

First, let's find the circumference of the 210° section of the circle.

The circumference of the the cone is .  We can use this to find the radius .

When you fold the 210° section into a cone, the slant height is the original radius of 10.  We can use the radius and slant height of the cone to form a right triangle with the height.  Use the Pythagorean Theorem to find the height.

radius² + height² = slant height²

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺

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