Answer:
101
Step-by-step explanation:
According to the Law of Cosines, for any △ABC with side lengths a, b, and c, a2=b2+c2−2bccosA; b2=a2+c2−2accosB; and c2=a2+b2−2abcosC
.
The Law of Cosines can be used because all three side lentghs are known.
Set up the equation for the Law of Cosines:
a2=b2+c2−2bccosA
Substitute the known values into the Law of Cosines:
312=222+182−2(22)(18)cosA
Square the values and multiply:
961=484+324−792cosA
Add:
961=808−792cosA
Subtract 808
from both sides:
153=−792cosA
Divide both sides by −792
:
153−792=cosA
According to this equation m∠A
is equal to the inverse cosine function of −153792
. Write this:
m∠A=cos−1(−153792)
Calculate the value of the inverse cosine −153792
on a calculator:
m∠A≈101°
Therefore, m∠A≈101°
.
Slope: (y2-y1)/(x2-x1) = m
Find the slope, m, then pick a point, plug in the x, y, and m, and solve for b in the equation:
y = mx + b
That is your y-intercept.
Take out your x and y, plug in m and b, and that is your generic form for your line, t.
Step-by-step explanation:
To find the perimeter of something, we add all of the measurements of the sides together.
A rectangle has 4 sides, this means we must double the algebraic hints given to us.
If we add them all up together it will look like this:
x-9+x-9+3x-4+3x-4=138
If we simplify it by collecting the like terms:
8x-26=138
We add 26 onto 138
8x=164
To find out what x equals, we divide by 8:
164÷8= 20.5
Answer:
x=20.5cm
x-9 is 11.5
3x-4 is 57.5
I know that you will not give 100 points but just wanted to help.
105 but I need 20 characters to
