After a rotation of 90° about the origin, the coordinates of the vertices of the image of a triangle are a'(6, 3), b'(-2, 1),
and c'(1,7). what are the coordinates of the vertices of the pre-image?

A(-3, 6), B(-1, -2), C(-7, 1)

Step-by-step explanation:

To the pre-image after a 270°-counterclockwise rotation [90°-clockwise rotation], just reverse it by doing a 270°-clockwise rotation [90°-counterclockwise rotation]:

Extended Rotation Rules

So, perform your rotation:

270°-clockwise rotation [90°-counterclockwise rotation] → C'[1, 7] was originally at C[-7, 1]

→ B'[-2, 1] was originally at B[-1, -2]

→ A'[6, 3] was originally at A[-3, 6]

I am joyous to assist you anytime.

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 ☺

for the free

< < < emily> > >