Answer:
Step-by-step explanation:
let speed of Stephen=x mph
speed of Diana=x+4
then
6x+6(x+4)=276
divide by 6
x+x+4=276/6=46
2x=46-4=42
x=42/2=21
Stephen is traveling at 21 mph.
Diana is traveling at 21+4=25 mph.
y=2x+2
126?? i think
A triangle always ahs a total of 180 degrees, so I added 24+28+6= 54, then subtracted it by 180 and got 126
(Dont fully trust me, im not an expert in geometry :P)