In a triangle ΔABC, the sides DE parallel to BC and AD = 6 cm, DB = 9 cm, AE = 8 cm, find the value of AC.

If the ratio of the measurements of the three angles of a triangle is 2: 3: 4, then the measurement of its largest angle is.

ABCD is a trapezium in which AB is parallel to CD and AB = 4 ( CD ) . The diagonals of the trapezium intersects at O. what is the ratio of area of triangle DCO to the area of the triangle ABO ?

Find the second diagonal of a rhombus when it’s first diagonal length is 12 cm and its side is 10 cm?

In ΔABC, ∠C=90° and CD is perpendicular to AB at D. If AD/BD=, then AC/BC=?

P and Q are center of two circles with radii 9 cm and 2 cm respectively, where PQ = 17 cm, R is the center of another circle of radius x cm, which touches each of the above two circles externally. If ∠PRQ = 90 °, then the value of x is 

If there are four lines in a plane, then what cannot be the number of points of intersection of these lines? 

If in a triangle, the orthocenter lies on vertex, then the triangle is