Question

ABC is a triangle, right-angled at C. If AB = 15 cm and AC = 12 cm, then BC = ____ *
1 point
9 cm
27 cm
81 cm
3 cm​

Answer 1

if Triangle ABC is right angled at C then ,

AB is hypotenuse, BC and CA are bases

so , AB²= BC²+ CA²

or, 15² = BC²+12²

or, BC² = 225- 144 = 81

or, BC =√81 = 9cm

Answer 2

Given :

• ABC is a right angled Triangle in which AB = 15 cm and AC = 12 cm .

To Find :

• Length of BC .

Solution :

$\longmapsto\tt{AB=15\:cm}$

$\longmapsto\tt{AC=12\:cm}$

By Pythagoras Theorem :

$\longmapsto\tt{{(H)}^{2}={(B)}^{2}+{(P)}^{2}}$

$\longmapsto\tt{{(15)}^{2}={(B)}^{2}+{(12)}^{2}}$

$\longmapsto\tt{225-144={(B)}^{2}}$

$\longmapsto\tt{\sqrt{81}=B}$

$\longmapsto\tt\bf{9\:cm=B}$

So , The Length of BC is 9 cm .

Option A) 9 cm is Correct .