A piece of wire is in the form of a sector of a circle of radius 20 cm, subtending an angle \( 150^{\circ} \) at the centre. If it is bent in the form of a circle, then what will be its radius?
Suppose P, Q and R are the mid-points of sides of a triangle of area \( 128 cm^{2} \). If a triangle ABC is drawn by joining the mid-points of sides of triangle PQR, then what is the area of triangle ABC?
Let two lines p and q be parallel. Consider two points B and C on the line p and two points D and E on the line q. The line through B and E intersects the line through C and D at A in between the two lines p and q. If AC : AD = 4 : 9, then what is the ratio of area of triangle ABC to that of triangle ADE?
All the four sides of a parallelogram are of equal length. The diagonals are in the ratio 1 : 2. If the sum of the lengths of the diagonals is 12 cm, then what is the area of the parallelogram?
ABC is a triangle right angled at B. If AB = 5 cm and BC = 10 cm, then what is the length of the perpendicular drawn from the vertex B to the hypotenuse?