In degrees: 3π/4 radians = 135°
Angle of x=135° is in the 2nd Quadrant and has negative cos x values and positive sin x values.
cos 135° = cos ( 90° + 45°)= - sin 45° =

sin 135° = sin ( 90° + 45° ) = cos 45° =

. You can also see the graph in the attachment.
Answer:
70cm
Step-by-step explanation:
,
Since, both of the tank posses the same quantity of water then there volume is the same thing
For rectangular base
Volume= (Lenght × breadth × hheight)
If we substitute values
Lenght= 80 cm
Breadth= 70 cm
height= 45 cm
Volume= 80cm × 70cm × 45cm
Volume= 252000cm^3
For square base
Volume= (side)^2 × height
side =60cm.
But volume of square base= volume of
rectangular base
252000cm^3= 60^2 × height
Height= (252000cm^3)/(60^2 )
Height= 70 cm
Hence, the second tank is 70 cm deep
9,899 = 206x
He divided by 206
He got 48.053 and rounded up to 49
My using the equation, we can see that he is correct.
Isolate the x. Note the equal sign. What you do to one side you do to the other.
Subtract 2y from both sides
2x + 2y (-2y) = 10 (-2y)
2x = 10 - 2y
Isolate the x, divide 2 from both sides and from all terms.
(2x)/2 = (10 - 2y)/2
x = 5 - y
Place the variable in the front
x = -y + 5
x = -y + 5 is your answer
hope this helps
Increased by 15
past score was x
increased by 15 means he raised to 15+x
it was raised to 83%
therefor
x+15=83
first option is right (and first test was 68%)