The correct answer is the first choice
Answer:
12
Step-by-step explanation:
We know that AD=BC and that AB=CD. We also know the perimeter of the rectangle ABCD to be 54 units.
From this, we can add up the sides which will be equal to 54 units.
AD+BC+AB+CD=54
2x+2x+3x-3+3x-3=54
10x=60
x=6
Since we are trying to find the length of side BC we substitute this value back into 2x.
BC=2x =2*6=12
Therefore, the length of BC is 12 units.
Answer: y = 7.5
Step-by-step explanation:
Suppose that y varies directly with x
That is, y∝x
Convert y∝x to a full equation by introducing a constant k to the right hand side.
Therefore, y = kx
Given that y = 10 and x = 20
Substitute y and x in the equation above. We have;
10 = k(20)
10 = 20k
20k = 10
k = 10/20
k = 0.5
Since k = 0.5, the equation y = kx becomes y = 0.5x
Now, to find y if x = 15, substitute x in equation y = 0.5x
Therefore, y = 0.5(15)
y = 7.5
Answer:
k = -9.
Step-by-step explanation:
As the triangle is right-angled at Q, by Pythagoras:
PR^2 = PQ^2 + RQ^2
So, substituting the given data and using the distance formula between 2 points:
(7 - 1)^2 + (k - 4)^2 = (-4-4)^2 + (-3-1)^2 + (7 - (-3))^2 + (k - (-4))^2
36 + (k - 4)^2 = 64 + 16 + 100 + ( k + 4)^2
(k - 4)^2 - (k + 4)^2 = 180 - 36
k^2 - 8k + 16 - (k^2 + 8k + 16) = 144
-16k = 144
k = -9.
Use math-way!!!!!!! I promise you won’t need to waist your points.%