Hi guys just need some help.

being given this and havent got a clue.

if you could work it out and then explain that would be great

Points P+Q are on opposite sides of a straight tunnel. A third point R forms a triangle PQR. S+T are established along the sides PR and QR repectively such that

PR= 312m

SR= 116m

ST= 275m

QR= 423m

RT= 287m

I need to calculate the length of the tunnel assuming that all points are in the same place.

Thanks PPL

James