Find the surface area ( in ${\mathrm{cm}}^2$ ) of tetrahedron $ABCD$ when all of the faces are equilateral triangles with side length $10$ cm. (Round answer to the nearest integer)

Find the area ( in ${\mathrm{m}}^2$ ) of a regular pentagon of radius $4$ cm. (Round answer to the nearest integer)

Find the value of $x$ when the area of this triangle is $5\sqrt{3}$.

Find the value of $\theta$ in the triangle 

Find the value of $\theta$ in the triangle 

Find the value of $\theta$ in the triangle 

Find the value of $\theta$ in the triangle 

Find the value of $\theta$ in the triangle 

Find the value of $\theta$ in the triangle