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Mathematics · 2023 · 3 marks
CBSE 2023 · Region 1 · Set 2 · Q26
The centre of a circle is (2a, a -7). Find the values of 'a' if the circle passes through the point (11, -9). Radius of the circle is 5 √ 2 cm.
The centre of a circle is (2a, a -$\displaystyle 7$). Find the values of 'a' if the circle passes through the point $\displaystyle (11, -9)$. Radius of the circle is $\displaystyle 5 \sqrt{2} \mathrm{~cm}$.
Marking-scheme solution
\(\displaystyle (2 a-11)^{2}+(a-7+9)^{2}=(5 \sqrt{2})^{2}\)
\(\displaystyle \Rightarrow 5 \mathrm{a}^{2}-40 \mathrm{a}+75=0\)
\(\displaystyle \Rightarrow(\mathrm{a}-5)(5 \mathrm{a}-15)=0\)
\(\displaystyle \mathrm{a}=5, \mathrm{a}=3\)
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CBSE Class 10 Mathematics past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.