Chapter 5
I’m Up and Down, and Round and Round
CBSE Class 9
Mathematics Solutions
Educart Mathematics class Class 9 NCERT Exemplar cover
Question:

The distance of a chord of length 16 cm from the centre of a circle is 6 cm. Find the radius of the circle.

Answer: Verified

Chord length, AB = 16 cm
Half chord, AM = 8 cm
Distance from centre to chord, OM = 6 cm
Let rr be the radius.

Answer image

In the right triangle OAM, OA2=AM2+OM2  ⟹  r2=82+62<spanclass="katex−error"title="ParseError:KaTeXparseerror:Can′tusefunction′OA^2 = AM^2 + OM^2 \implies r^2 = 8^2 + 6^2<span class="katex-error" title="ParseError: KaTeX parse error: Can't use function '' in math mode at position 1: ̲r^2 = 64 + 36 \…" style="color:#cc0000">r^2 = 64 + 36 \implies r^2 = 100 \implies r = 10 \text{ cm} Hence, the radius of the circle is 10 cm.

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