Answer:
15
Step-by-step explanation:
substitute the values that are given into the expression.
c + a = x
12 + 3 = x
15 = x
X^2+10x+16=0
First, you find factors of 16.
1 x 16
2 x 8
4 x 4
Next, you find which of the factor pairs adds up to 10 (from the 10x). In this case, 2 x 8 because 2 times 8 is 16 and 2 plus 8 is 10.
Then, the equation will be written out as: (x+2) (x+8). Take those two equations and set them equal to 0, and then solve.
x+2=0
-2 -2
x=-2
x+8=0
-8 -8
x=-8
So, your answers are x=-2 and x=-8. You can check by plugging in those two numbers as x.
So the length is 4*28=112mm
The width would be calculated like this:
you draw an equilateral triangle in the middle with sides or 2r(56mm). The based on pythagorean theorem u know that
h=rad(56^2-28^2)=48.497
28+28+h=104.497
The area would be S=l*w which is 11703.7113mm