Question

3. ABC is a triangle in which AB = AC = 4 cm
and ZA = 90°. Calculate :
(i) the area of A ABC,
(ii) the length of perpendicular from A to BC.​

Answer 1

area of triangle ABC = 1/2 ×BASE × HEIGHT

= 1/2 × AB × AC

= 1/2 × 4× 4

= 2 × 4

= 8 cm square

LET AD IS PERPENDICULAR TO BC

In Triangle ADB AND ADC

AD = AD ( common)

angle ADC = angle ADB ( each 90 degree)

AB = AC (Given)

Triangle ADB (congruent to). triangle ADC ( RHS criteria)

BD = CD ( cpct )

in triangle ABC , BY Pythagoras theorem