HELPPPP GET 25PTS!!
1 answer:
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Answers:
x = 100
y = 25
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Explanation:
Angle y and the 25 degree angle are corresponding angle. Because the lines are parallel, this means that y = 25
Check out the attached image. Using a red pen, I extended one of the lines to form a triangle. From the alternate interior angle theorem, we know that one of the angles of the triangle is 75 degrees (alternate interior angles are congruent). Again this stems from the fact that the lines are parallel.
I've also introduced the variable z to help find x. The angles x and z add up to 180 degrees since they form a straight line. So we need to find z before we can find x.
The triangle's angles 25, 75, z add up to 180. Let's solve for z
25+75+z = 180
100+z = 180
z = 180-100
z = 80
Use this to find x
x+z = 180
x+80 = 180
x = 180-80
x = 100
Answer: The length is 13cm and the width is 7cm
Step-by-step explanation:
For a rectangle of length L and width W, the area is:
A = W*L
In this case we have:
L = (2*x + 9) cm
W=(3*x + 1) cm
Then the area of the rectangle is:
A = (2*x + 9)*(3*x + 1) cm^2
A = (6*x^2 + 2*x + 27*x + 9) cm^2
A = (6*x^2 + 29*x + 9) cm^2
now we remove two squares with sides of x cm
The area of each one of these squares is (x cm)*(x cm) = x^2 cm^2
Then the area of the figure will be:
area = (6*x^2 + 29*x + 9) cm^2 - (2*x^2 ) cm^2
area = (4*x^2 + 29*x + 9) cm^2
Now we know that the area of this shape is 83 cm^2, then we need to solve:
83 cm^2 = (4*x^2 + 29*x + 9) cm^2
0 = (4*x^2 + 29*x + 9) cm^2 - 83 cm^2
0 = (4*x^2 + 29*x - 74) cm^2
Then we need to solve:
0 = 4*x^2 + 29*x - 74
Here we can use Bhaskara's equation, the solutions of this equation are given by:
Then the two solutions are:
x = (-29 - 45)/8 = -9.25 (for how the length and width are defined, we can not have x as a negative number, then this solution can be discarded).
The other solution is:
x = (-29 + 45)/8 = 2
x = 2
Then the length and width of the rectangle are:
Length = (2*2 + 9)cm = 13 cm
Width = (3*2 + 1)cm = 7cm