Use the diagram to find the angle measures of triangle recall that the sum of the angle measures of a triangle 180

x=19º

x+9=28º

7x=133º

Step-by-step explanation:

x+9+x+7x=180

9x+9=180

9x=180-9

9x=171

x=19

Bottom left angle is 19°

Bottom right angle is 28°

Top angle is 133°

Step-by-step explanation:

Since all angles of a triangle add up to 180° we know x + 7x + x+9=180. then we combine like terms to get 9x+9=180. Next, we do inverse operation to find X. First subtract 9 from both sides of the equation to get 9x=171 then divide 9 from both sides to get x=19. No that we know x, we can find the values of the angles by putting in 19 for x. Bottom left angle is 19°, bottom right angle is 28°, top angle is 133°.

50-38=12

step-by-step explanation:

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 ☺