$\bf \qquad \qquad \textit{direct proportional variation}\\\\
\textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby 
\begin{array}{llll}
k=constant\ of\\
\qquad variation
\end{array}\\\\
-------------------------------\\\\
\textit{we also know that }
\begin{cases}
y=\frac{1}{2}\\
x=2
\end{cases}\implies \cfrac{1}{2}=k2\implies \cfrac{1}{4}=k
\\\\\\
\boxed{y=\cfrac{1}{4}x}
\\\\\\
\textit{when x=3, what is \underline{y}?}\qquad y=\cfrac{1}{4}\cdot 3$

4 0

3 years ago

A wrestling match has eliminations each round. The table below shows the number of wrestlers in each of the first 4 rounds of th

AlladinOne [14]

$\bf \begin{array}{lllll}
round(x)&\boxed{1}&2&3&\boxed{4}\\\\
wrestlers[f(x)]&\boxed{64}&32&18&\boxed{9}
\end{array}
\\\\\\
slope = {{ m}}= \cfrac{rise}{run} \implies 
\cfrac{{{ f(x_2)}}-{{ f(x_1)}}}{{{ x_2}}-{{ x_1}}}\impliedby 
\begin{array}{llll}
average\ rate\\
of\ change
\end{array}\\\\
-------------------------------\\\\
f(x)= \qquad 
\begin{cases}
x_1=1\\
x_2=4
\end{cases}\implies \cfrac{f(4)-f(1)}{4-1}\implies \cfrac{9-64}{4-1}\implies \cfrac{-55}{3}$

55 over 3, or 55 wrestlers for every 3 rounds, but the wrestlers value is negative, thus 55 "less" wrestlers for every 3 rounds on average.

6 0

3 years ago

Read 2 more answers

I dont really know how to do soh cah toah. please help me find x.

Ipatiy [6.2K]

First notice that the triangle with sides $x,y,a$ and the triangle with sides $z,a+b,x$ are similar. This is true because the angle between sides $x,y$ in the smaller triangle is clearly $30^\circ$ , while the angle between sides $y,z$ in the larger triangle is clearly $60^\circ$ . So the triangles are similar with sides $x,y,a$ corresponding to $a+b,z,x$ , respectively.

Now both triangles are $30^\circ-60^\circ-90^\circ$ , which means there's a convenient ratio between its sides. If the length of the shortest leg is $\ell_1$ , then the length of the longer leg is $\ell_2=\sqrt3\ell_1$ and the hypotenuse has length $\ell_3=\sqrt{{\ell_1}^2+{\ell_2}^2}=2\ell_1$ .

Since $x$ is the shortest leg in the larger triangle, it follows that $a+b=2x$ , so $a+b=15=2x\implies x=\dfrac{15}2$

4 0

3 years ago