Question

AABC is right angled at B. BD is the perpendicular to
AC. If AB = 3 cm, AC = 5 cm and BC = 4 cm. Find out BD.​

Answer 1

Step-by-step explanation:

ABC is a right triangle, right angled at B, with AB= 3cm and BC=4cm. BD is drawn perpendicular to the hypotenuse AC. What is the length of BD if AC= 5cm? I can find only similar triangles side proportion theorem.

Method-1

AD=(AB)cosA

AD=3×cos(b2+c2−a22bc)

AD=3×cos(52+32−422×5×3)

AD=1.8

BD2=AB2−AD2

BD2=32−1.82

BD=2.4

Answer 2

Answer:

2.4

Step-by-step explanation:

1/BD^2 = 1/BC^2 + 1/AB^2

= 1/4^2 + 1/3^2

=1/16 + 1/9

1/BD^2 = 25/144

BD^2 = 144/25

SQUARE ROOTING BOTH SIDES

BD = 12/5

BD = 2.4