Question

​ △BCD ​ is a right triangle. The length of the hypotenuse is 19 centimeters. The length of one of the legs is 13 centimeters.

Answer 1

here we can use Pythogoras' theorem.
in right angled triangles the square of the hypotenuse is equal to the sum of the squares of the other 2 sides.
hypotenuse is 19 cm. One side is 13 cm and we need to find the length of the third side.
                                                                         
19² = 13² + X² 
X - length of the third side
                                                           
361 = 169 + X² 
X² = 361 - 169
                                                                     
X² = 192
                                                                             
X = 13.85 the length of third side rounded off to the nearest tenth is 13.9 cm