I assume that you are referring to degrees here: "...[30-60-90] right triangle".
With such a right triangle the ratio of shorter leg to hypotenuse is :
Use this formula and the Pythagorean theorem to calculate the missing values:
to #1: Solve the equation
for h and afterwards calculate the shorter leg.
The following questions have to be done similarly.
If the side of the square is a and the diagonal is d you find:
. Use this property to calculate the length of one side and afterwards the perimeter:
The altitude of an isosceles triangle with the side a is calculated by: .
Plug in the known value of h and solve for a. Afterwards calculate the perimeter: