Question

In a right angled triangle ABC, angle B = 90°. If AB= 8, BC = 15,find the perimeter of ∆ ABC​

Answer 1

Answer:

40 cm

Step-by-step explanation:

in ∆ABC, ANGLE B =90°

=> AB²+ BC²= AC²( PYTHAGORAS THEOREM)

=> AC =√15²+8²

= 17

PERIMETER= AB+BC+AC

=> 8+15+17

= 49 CM

Answer 2

ǟռֆաɛʀ :

9 cm

ɢɨʋɛռ :

AB = 8 cm

BC = 15 cm

∠B = 90°

քʀօօʄ :

Using Pythagoras theorem in ∆ ABC​

(AB)² + (BC)² = (AC)²

(15)² + (8)² =  (AC)²

(AC)² = 225 + 64

(AC)² = 289

AC = √289

AC = 17 cm

Now in radius r = ∆ / s

where ∆ is area of triangle and s is semi perimeter.

∆ = 1/2 × 8 × 15

∆ = 60

s = 8 + 15 + 17 / 2

s = 40/2

s = 20

=>  r = ∆ / s

=> r = 60 / 20

=> r = 3cm

We have found our radius that is 3cm for finding perimeter we need to find diameter.

So radius multiply by radius = diameter

.ie. r × r = d

3 × 3 = 9cm

Diameter is 9cm

∴ Perimeter is also 9 cm