A triangle has sides 5 cm, 12 cm and 13 cm. Find the length to one decimal place, of the perpendicular from the opposite vertex to the side whose length is 13 cm.
Let, AB = 5cm, BC = 12 cm and AC = 13 cm. Then, AC2 = AB2 + BC2. This proves that ΔABC is a right triangle, right angles at B. Let BD be the length of perpendicular from B on AC.
Now, Area ΔABC `=1/2(BCxxBA)`
Also, Area of ΔABC `=1/2ACxxBD=1/2(13xxBD)`