Help me on this i wanna pass so do not answer for points or you get banned

What is the length x of the side of the triangle below? (hint: use the cosine function)

Abeam of electrons with of wavelength of 7.5 x 10-6 m is incident on a pair of narrow rectangular slits separated by 0.75 mm. the resulting interference pattern is projected onto a screen 10.0 m from the slits. what is the separation of the interference maxima in the resulting interference pattern?

The respiratory system removes oxygen and water from the body. select the best answer from the choices provided t f