All circles are
ACongruent only if radii are equal
BAlways similar to each other
CAlways congruent to each other
DNever similar unless radii are equal
Answer & Solution
Correct answer: B. Always similar to each other
1. Any two circles have the same shape (round).
2. They differ only by scale (radius), which is the definition of similarity.
3. So all circles are always similar.
_Source: NCERT Class 10 Mathematics, Ch 6 "Triangles", §6.2_
Related questions
In triangle ABC, AB squared + BC squared = AC squared and AB = BC. The angles of the trianTriangles ABC and DEF are similar with AB = 4 cm, BC = 5 cm, CA = 6 cm and EF = 7.5 cm. ThIn a quadrilateral ABCD where AB is parallel to CD and the diagonals AC and BD intersect aABC is an equilateral triangle of side 2a. The length of its altitude isThe sides of a triangle are in the ratio 3 : 4 : 5 and its perimeter is 60 cm. The area ofIn triangle ABC, AD is perpendicular to BC. Given AB = 7 cm, AC = 25 cm, BD = 5 cm, the vaTwo similar triangles have areas 81 sq cm and 144 sq cm. The ratio of their corresponding In an isosceles triangle ABC with AB = AC = 13 cm and BC = 10 cm, the altitude from A to B