Question

In the given figure, the length of the rectangle is 12 cm and its diagonal is 13 cm.
Find its perimeter.
13 cm
B
12 cm​

Answer 1

Answer:

the length =12 cm, and diagonal =13cm.

if we divide the rectangle diagonally, we get a right angled triangle, and by using Pythagoras theorem :

(h)2 = (p)2 + (b)2 [where 2 is the square]

13*13 = (p)2 + 12*12

169= (p)2 +144

(p)2 = 169-144

(p)2 = 25

p = [root over]25

p= 5 cm

therefore the breadth of the rectangle =5 cm

and to find the perimeter :

perimeter of rectangle =2(length+breadth)

peri= 2(12+5)

peri=2*17

perimeter of rectangle = 34 cm

hope the answer helps :)

Answer 2

given that length =12cm ,and diagonal =13cm

each angle =90degree

there form a triangle ABC

so in triangle ABC

(CD)square =(CB) sq +(AB) sq

(13) sq = (CB)sq + (12)sq

169=(CB)sq + 144

169 - 144=(CB)sq

25 =(CB ) sq

√25=CB

5=CB

Perimeter of rectangle=2(l+b)

2×12 +5=34