Question

plz solve it as soon as possible ​

Answer 1

Answer:

4 cm

Step-by-step explanation:

ΔABC is a right angled triangle with ∠B = 90°

AB = 3cm, BC = 12 cm. AC is the hypotenuse

Using Pythagoras theorem.

AC² = AB² + BC²

        = 9 + 144 = 153

AC = √153 cm.

Now ΔACD is a right angled triangle with ∠C = 90°

Using Pythagoras theorem

AD² = AC² + CD²

CD² = AD² - AC² = (13)² - (√153)² = 169 - 153 = 16

CD = √16 = 4 cm.