Which of the following CANNOT be attributed directly

Find the area of triangle having sides 5 m, 6 m, and 9 m.

If in a right angle triangle ABC, Angle B is a right angle. AB = 20 cm, BC= 21 cm if BD is perpendicular to AC find the length of BD? 

The length of the each side of an equilateral triangle is 63√3 cm . The area of circumcircle, (cm ² ) is

If G is the centroid and AD, BE, CF are three medians of ∆ABC with area 78 cm ² , then the area of ∆BGF is?

ABCD is a square. P, Q, R and S are points on the sides AB, BC, CD and DA respectively such that AP = BQ = CR = DS. Angle  SPQ equal to ?

Let A, B, and C be the mid-points of sides PQ, and QR PR, respectively, of ΔPQR. If the area of ΔPQR is 64cm², then find the area of ΔABC.

One chord of a circle is given as 21.5 cm. Then the radius (r) of the circle must be: