Its a simultaneous equation:
lets make "x" the used games and "y" the new ones
4x + 2y = 84
6x + y = 78. (multiply this by 2 to cancel out y)
12x + 2y = 156
so now we subtract them:
12x - 4x = 156 - 84
x = 9
used games cost $9
new games cost 78 - 6(9) = $24
Janet has $120 but she already bought 3 NEW games so:
120 - 3(24) = $48 left
48/9 = how many used ones she can buy = 5. something
she can buy 5 used
500 because you would round down because it is less than 5.
The diameter is 24 since if you ÷ it by 2 you get 12 to get area it is radius squared so 12 × 12= 144×pi which is 3.14= 452.16 mm you can even check in a calculator
Answer:
Step-by-step explanation:
The area of the big triangle is 1/2 b h = 1/2*6*(12^2 = 6^2 + x^2)
that ends up being 
the small triangle are needs to be subtracted....
that is the length of the unknown side...
1/2 B * h of that triangle get you to 
just subtract the two areas
