Derivative of tan^2 x

What value of x will make the triangles similar by the sss similarity theorem?

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

Ametal rod needs to be 9 feet and 5.5 inches in length. the sections of the poles being used are each 1 foot and 10.5 inches long. how many 1ft 10.5in sections would be needed to complete the 9ft 5.5in metal rod? and how many inches of material will be left?