HELP PLS THE TEACHER ID MEAN LOL

ANEK [815]

Sine 61 = RS / hypotenuse
RS = Sine 61 * hypotenuse
RS = 0.87462 * 8
RS = 6.99696

3 0

2 years ago

Whats 19.8 to 1 significant figure

Crank

19.8 rounded to 1 s.f. is 20

6 0

2 years ago

Rajan needs 1 liter of 15% hydrochloric acid solution for an experiment. He checks his storage cabinet, but he only has a 5-lite

yarga [219]

Answer:

Rajan must use 0.75 liters of 5% hydrochloric acid solution and 0.25 liters of 45% hydrochloric acid solution.

Step-by-step explanation:

Let us assume that, x liters of the 5% hydrochloric acid and y liters of the 45% hydrochloric acid solutions are combined.

As Rajan need total of 1 liter of solution, so

$x+y=1$

i.e $x=1-y$ --------------------1

As Rajan needs 5% hydrochloric acid and 45% hydrochloric acid to make a 1 liter batch of 15% hydrochloric acid, hence acid content of the mixture of two acids will be same as of the final one, so

$0.05x+0.45y=1\times 0.15$

i.e $5x+45y=15$ -------------2

Putting value of x from equation 1 in equation 2,

$\Rightarrow 5(1-y)+45y=15$

$\Rightarrow 5-5y+45y=15$

$\Rightarrow 5+40y=15$

$\Rightarrow 40y=15-5=10$

$\Rightarrow y=0.25$

Putting the value of y in equation 1,

$x=1-0.25=0.75$

Therefore, Rajan must use 0.75 liters of 5% hydrochloric acid solution and 0.25 liters of 45% hydrochloric acid solution.

5 0

3 years ago

A long jumper lifts off 3 m after starting his run, and lands 6 m later. When he is 8 m from the start line, he is 5 cm above an

slega [8]

Answer:

The equation of the parabola that models the path of the long jumper through the air is $y = -x^{2}+12\cdot x -27$ .

Step-by-step explanation:

Mathematically, we know that parabolas are second-order polynomials and every second-order polynomials, also known as quadratic functions, can be constructed by knowing three different points of the curve. The standard form of the parabola is:

$y = a\cdot x^{2}+b\cdot x + c$

Where:

$x$ - Horizontal distance from the start line, measured in meters.

$y$ - Height of the long jumper, measured in meters.

$a$ , $b$ , $c$ - Polynomial constants, measured in $\frac{1}{m}$ , dimensionless and meters, respectively.

If we know that $(x_{1},y_{1}) = (3\,m, 0\,m)$ , $(x_{2},y_{2}) = (8\,m, 0.05\,m)$ and $(x_{3}, y_{3}) = (9\,m, 0\,m)$ , this system of linear equations is presented below:

$9\cdot a + 3\cdot b + c = 0$ (Eq. 1)

$81\cdot a + 9\cdot b + c = 0$ (Eq. 2)

$64\cdot a + 8\cdot b + c = 0.05$ (Eq. 3)

The coefficients of the polynomial are, respectively:

$a = -\frac{1}{100}$ , $b = \frac{3}{25}$ , $c = -\frac{27}{100}$

The equation of the parabola that models the path of the long jumper through the air is $y' = -\frac{1}{100}\cdot x^{2}+\frac{3}{25}\cdot x -\frac{27}{100}$ .

But we need $y$ measured in centimeters, then, we use the following conversion:

$y = 100\cdot y'$

Then, we get that:

$y = -x^{2}+12\cdot x -27$

Where $x$ and $y$ are measured in meters and centimeters, respectively.

The equation of the parabola that models the path of the long jumper through the air is $y = -x^{2}+12\cdot x -27$ .

4 0

2 years ago

Use the distributive property to create an equivalent expression to 7(2j + 3 + 2j).

Scorpion4ik [409]

Answer:

28j + 21

Step-by-step explanation:

combine like terms

7(2j+ 3+ 2j)

7(4j+3)

Distribute

7(4j + 3)

=

28j + 21

6 0

2 years ago

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