Which of the following is not the right reason for

An angle is equal to 3/7 of its supplement. The angle is :

In ∆ABC, AD = DB , DE is parallel to BC, and the area of ∆ABC is 20 cm². What is the area of ∆ADE in cm² ?

The ratio of the angles ∠A and ∠B of a non-square rhombus ABCD is 7:5, then the value of the ∠C is

In ∆ABC , G is the centroid , AB = 18 cm, BC= 24 cm and AC = 30 cm , find GD, where D is the mid-point of BC?

The length of the each side of an equilateral triangle is 42√3. The area of incircle, (cm ² ) is

The radius of the incircle of a triangle is 6 cm. if the area of the triangle is 30 cm ² , then its perimeter is?

Find the ratio between the area of the in-circle and the circum-circle of a square?

In ∆ABC , G is the centroid , AB = 20 cm, BC= 24 cm and AC = 28 cm , find GD, where D is the mid-point of BC?

If the area of ∆ ABC is 30 cm² & G is the centroid of ∆ ABC.then the area of the ∆ AGB?