the length of each side of the ABCD EFGH cube is 6cm. If point P is located in the middle of line EH, point Q is in the middle of line EF, and point R is in the middle of line AE, determine the distance of point E to the PQR plane

           The distance is:  

Step-by-step explanation:

The distance of point E to the PQR plane it is the hight (vertical) of piramid PRQE

If point P is located in the middle of line EH, point Q is in the middle of line EF, and point R is in the middle of line AE than:

EP = EQ = ER = 0.5EF = 3 cm  and  m∠REQ = m∠QEP = m∠REP = 90° so triangles RQE, QPE and PRE are congruent.

RQ = QP = PR so triangle PQR is equilateral and from Pythagorean theorem (for ΔRQE):

Then:

and:  

Therefore from Pythagorean theorem (for ΔERK):