in triangle ABC , angle A =900 , AB = 5cm and AC = 12cm if AD is - Maths - Triangles

Question

in triangle ABC , angle A =900 , AB = 5cm and AC =
12cm if AD is perpendicular to BC , then AD = ?
de options r
a 13/2
b 60/13
c 13/60
d 2root15 / 13
plz answer and also justify plz!!

Satyajit Mohanty · Accepted Answer

b)60 / 13
<img src=
"http://www%20euclideanspace%20com/maths/geometry/trig/triangles/acute%20gif"
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in this A = 900
In triangle ABC
AB2 + AC2 = BC2
---> BC = root(144 + 25) = root(169) = 13 cm
In triangle ADC and triangle ABC
angle BAC = angle ADC = 900
angle ACB = angle DCA [common angle]
Hence
triangle ADC ~ triangle ABC [A-A postulate]
As both traingles r similar
then according to sides theorem :-
BC / AC = AB / AD
----> 13 / 12 = 5 / AD
----> AD = 60 / 13 (ans)
Hope this helps !!!

in triangle ABC , angle A =900 , AB = 5cm and AC = 12cm . if AD is perpendicular to BC , then AD = ? de options r ....a. 13/2b. 60/13c. 13/60d. 2root15 / 13 plz answer...and also justify...plz!!

in triangle ABC , angle A =90⁰ , AB = 5cm and AC = 12cm . if AD is perpendicular to BC , then AD = ?

de options r ....
a. 13/2
b. 60/13
c. 13/60
d. 2root15 / 13

plz answer...and also justify...plz!!