1/3x + y = 4....subtract 1/3x from both sides
y = -1/3x + 4 <===
If there are 70 chairs but only 20 rows then that means he will have to set up 3.5 chairs per row, or Brook could set up 14 rows with 5 chairs in each row.
Srry if that didn't help but that's what i got from that.
Use trigonometric ratios.
Use angle(19)
Adjacent side of angle measure 19 is X
The hypotenuse is 21.
Use the cosine
Cos(19)=x/21
Plug in calculator
(21)cos(19)=19.85
Round to the nearest tenth. Which means the 8 rounds up to 9.
Answer: 19.9