$\triangle A B C$ is an isosceles triangle with $\angle$ C=90* and $ A C=5 cm. Then, A B=?
a) 25cm
b) 5cm
c) 10cm
d) $5 \sqrt{2} $cm
Given: ABC is an isosceles triangle, right-angled at C.
To Find: AB
![](/assets/questions/media/105375-25053-1599031580.png)
Solution:
Angle C = 90°
so, AB = hypotenuse,
AC = BC
In isosceles triangle two sides are equal.
AC = 5 ; BC = 5 ; AB = ?
Since its a right angled triangle, apply Pythagoras theorem,
$AB^2 = AC^2 + BC^2$
$AB^2 = 5^2 + 5^2$
$AB^2 = 25 + 25$
$AB^2 = 50$
$AB = √50$
$AB = √2 \times 5 \times 5$
So, the value of AB = 5√2
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