Answer:
2 cm^2/sec
Step-by-step explanation:
side of cube ---- x cm
volume = x^3
d(volume)/dt = 3x^2 dx/dt
when c = 20, d(volume)/dt = 10 cm^3/sec
10 = 3(20^2) dx/dt
dx/dt = 10/1200 = 1/120 cm/sec
Surface area = SA = 6x^2
d(SA)/dt = 12x dx/dt
so when x = 20, as above
d(SA)/dt = 12(20)(1/120) cm^2/sec
= 2 cm^2/sec
Answer:
AB = 10 and BC = 28
Step-by-step explanation:
The opposite sides of a parallelogram are congruent, thus
AB = DC, that is
3y - 2 = y + 6 ( subtract y from both sides )
2y - 2 = 6 ( add 2 to both sides )
2y = 8 ( divide both sides by 2 )
y = 4
Hence AB = 3y - 2 = (3 × 4) - 2 = 12 - 2 = 10
And
AD = BC, that is
2x - 4 = x + 12 ( subtract x from both sides )
x - 4 = 12 ( add 4 to both sides )
x = 16
Hence BC = x + 12 = 16 + 12 = 28
Answer:
(a) 412 ft
(b) 276 ft
Step-by-step explanation:
Consider the attached diagram.
(a) The internal angle of triangle RBT at B is 90° -10° = 80°. Since we know lengths RB and BT, we can find the length RT using the law of cosines:
RT² = RB² +BT² -2·RB·BT·cos(80°) = 190² +400² -2·190·400·cos(80°)
RT² ≈ 169,705.477
RT ≈ √169,705.477 ≈ 411.95
The guy wire to the hillside should be about 412 feet long.
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(b) The Pythagorean theorem can be used to find the shorter wire length.
LM² = LB² +MB²
LM = √(190² +200²) = √76,100
LM ≈ 275.86
The guy wire to the flat side should be about 276 feet long.
Answer:
Length + Length + Width + Width = Perimeter
Step-by-step explanation:
I can help you with some of these questions
1. The Great Wall of China is 13,170.696
2.how many feet are in a mile= 5,280= 1 mile
3. 19,536,000=3700 miles
