The ratio of boys to girls in Mrs.Graingers class is 3 to 2. what is the % of the class are boys

1 answer:

3 0

In plain and short, the whole class is 100%, so we first split it by the ratios, namely by 3+2, so 100/(3+2) and then give 3 pieces to the girls and 2 pieces to the boys, let's do so,

$\bf \cfrac{girls}{boys}\qquad 3:2\qquad \cfrac{3}{2}\qquad \qquad \cfrac{3\cdot \frac{100}{3+2}}{2\cdot \frac{100}{3+2}}\implies \cfrac{3\cdot 20}{2\cdot 20}\implies \cfrac{60}{40}$

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part 2. Find the value of the trig function indicated, use for that Pythagorean theorem to find the third side if you need it.

andreev551 [17]

Answer: $\bold{5)\ \cos \theta=\dfrac{\sqrt{11}}{6}\qquad 6)\ \tan \theta =\dfrac{8}{17}\qquad 7)\ \cos \theta = \dfrac{4}{3}\qquad 8)\ \cos \theta = \dfrac{\sqrt{10}}{10}}$

Step-by-Step Explanation:

Pythagorean Theorem is: a² + b² = c² , where "c" is the hypotenuse

$5)\ \cos \theta=\dfrac{\text{side adjacent to}\ \theta}{\text{hypotenuse of triangle}}=\dfrac{3\sqrt{11}}{18}\quad \rightarrow \large\boxed{\dfrac{\sqrt{11}}{6}}$

Note: (15)² + (3√11)² = hypotenuse² → hypotenuse = 18

$6)\ \cos \theta=\dfrac{\text{side adjacent to}\ \theta}{\text{hypotenuse of triangle}}=\dfrac{8}{17}\quad =\large\boxed{\dfrac{8}{17}}$

Note: 8² + 15² = hypotenuse² → hypotenuse = 17

$7)\ \tan \theta=\dfrac{\text{side opposite to}\ \theta}{\text{side adjacent to}\ \theta}=\dfrac{20}{15}\quad \rightarrow \large\boxed{\dfrac{4}{3}}$

Note: hypotenuse not needed for tan

$8)\ \cos \theta=\dfrac{\text{side adjacent to}\ \theta}{\text{hypotenuse of triangle}}=\dfrac{2}{2\sqrt{10}}\quad =\large\boxed{\dfrac{\sqrt{10}}{10}}$