Secant
- CBSE · NCERT Class 10, Ch 10 Circles
A secant is a line that cuts a circle at two different points.
A secant goes right through a circle, entering at one point and leaving at another. The piece of it inside the circle is a chord. Now slide the line away from the centre. The two points move closer until they meet. At that moment the line becomes a tangent. So a tangent is the special case of a secant whose two points have joined.
A small example
A circle has radius 5 cm. A line 3 cm from the centre is a secant. The chord it makes has half-length √(5² − 3²) = √16 = 4 cm, so the chord is 8 cm long. A line exactly 5 cm from the centre is a tangent. A line 6 cm away misses the circle.
Where marks go
CBSE's 2026-27 Maths Basic sample paper has a version of Question 24 for visually impaired candidates. Two circles share a centre, with radii 5 cm and 3 cm. A chord of the larger circle touches the smaller one. So one line is a secant of the big circle and a tangent to the small one.
The 2026-27 Maths Basic marking scheme gives half a mark to each of four steps. They are the right angle at the touching point and the half-chord of 4 cm. Then come the reason the chord is halved and the answer of 8 cm. Each written step earns its share under step marking.
Sources
Facts last checked against these sources on 30 September 2026.
- NCERT Mathematics, Class X, Chapter 10: Circles (reprint 2026-27) - section 10.1 · NCERT
- Mathematics Basic (241) Marking Scheme, Class X 2026-27 - Question 24 (visually impaired candidates) · CBSE Academic Unit
- Mathematics Basic (241) Sample Question Paper, Class X 2026-27 - Question 24 · CBSE Academic Unit
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