I love these. It's often called the Shoelace Formula. It actually works for the area of any 2D polygon.
We can derive it by first imagining our triangle in the first quadrant, one vertex at the origin, one at (a,b), one at (c,d), with (0,0),(a,b),(c,d) in counterclockwise order.
Our triangle is inscribed in the 
rectangle. There are three right triangles in that rectangle that aren't part of our triangle. When we subtract the area of the right triangles from the area of the rectangle we're left with the area S of our triangle.
That's the cross product in the purest form. When we're away from the origin, a arbitrary triangle with vertices 
will have the same area as one whose vertex C is translated to the origin.
We set 
That's a perfectly useful formula right there. But it's usually multiplied out:
That's the usual form, the sum of cross products. Let's line up our numbers to make it easier.
(1, 2), (3, 4), (−7, 7)
(−7, 7),(1, 2), (3, 4),
[tex]A = \frac 1 2 ( 1(7)-2(-7) + 3(2)-4(1) + -7(4) - (7)(3)
Answer:
b=44
b=44 - 9
b=44 + 5
x+x+x = 44
x + (x-9) + (x+5) = 44
3x - 4 = 44
+4
3x =48
÷3
x=16
So, first photo contains 16 birds.
x=16
(x-9) - - > 16-9 = 7
(x+5) - - >16+5=21
16 + 7 + 21 =44
Answer is 16 birds in first photo
Hope this helps!
Answer:
$179.20
Step-by-step explanation:
use the formula retail price = original price + markup
Step One: Convert 28% to a decimal
--> 0.28
Step two: Plug all the numbers into the equation
--> $140 + $140 x 0.28 = $179.20
Give brainliest if this was helpful! Thanks! Have an amazing day!
Answer: Part one (NEGATIVE) Part two is C (EVEN DEGREES OF FOUR OR GREATER)
Step-by-step explanation:
Step-by-step explanation:
function f was reflected over the x-axis and translated 2 units left
