Ok so you got -30+2r=4(4r-4)
You distribute and get -30+2r=16r-16
Then you subtract 16r on both sides to get -30-14r=-16, then you add 30 on both sides and get -14r=14 then divide both sides by -14 to get r by itself, so the answer is r=-1
Answer:
Volume of the frustum = 225.0952
Surface area = 274
Step-by-step explanation:
The volume can be calculated as the difference of the complete pyramid and the tip of the pyramid.
To find the height of the frustum, we can use pythagoras theorem in the following triangle:
first side: 9 - 5 = 4
second side h (height)
hypotenusa: slang = 6
6^2 = h^2 + 4^2
h^2 = 36 - 16 = 20
h = 4.4721
To find the height of the complete pyramid (H), we can use the following rule of three:
H / 9 = (H - 4.4721) / 5
5H = 9H - 40.2489
4H = 40.2489
H = 10.0622
Volume of complete pyramid:
V_complete = (1/3)*9^2*10.0622 = 271.6794
Volume of the tip:
V_tip = (1/3)*5^2*(10.0622 - 4.4721) = 46.5842
Volume of the frustum:
V_frustum = V_complete - V_tip = 225.0952
The surface area is the bigger base area + smaller base area + four side areas.
Bigger base area = 9^2 = 81
Smaller base area = 5^2 = 25
Side area = (9+5)*6/2 = 42
Total surface area: 81 + 25 + 4*42 = 274
I think it’s false sorry if you get it wrong
Answer:
90
Step-by-step explanation:
each dot = 45 bc 540 / how many dots there are which is 12 = 45 then there are 2 dots worth of 45 making it 90
math
540/12=45
45 x 2 = 90
