Question

Find the area of rhombus whose perimeter is 60 cm and one diagonal length is 18 cm

Answer 1

let sides of rhombus be a cm

(ATQ) 4a=60cm

a=15cm

diagonal of rhombus bisect each other at right angles

let OD =x cm

AO=9cm and angle AOB=90degree

By Pythagoras theorem,

15^2=9^2+x^2

225=81+x^2

144=x^2

x=12cm

therefore BD=24cm

area of rhombus=1/2*24*18=216cm^2

Answer 2

Answer:

let sides of rhombus be a cm

(ATQ) 4a=60cm

a=15cm

diagonal of rhombus bisect each other at right angles

let OD =x cm

AO=9cm and angle AOB=90degree

By Pythagoras theorem,

15^2=9^2+x^2

225=81+x^2

144=x^2

ANSWER= 144