Question

prove that a rhombus with one angle 90 is a squre

Answer 1

as we know that opposite angles of the rhombus are equal therefore 2 angles are 90...( i.e. the given one and opposite to it)
let the other 2 angles be x
now
x+x+90+90=360
2x=180
x=90
therefore the required angles of the rhombus are 90,90,90,90 and we know that all the sides of the rhombus are equal...hence it is a square..

Answer 2

Answer:

as we know that opposite angles of the rhombus are equal therefore 2 angles are 90...( i.e. the given one and opposite to it)

let the other 2 angles be x

now

x+x+90+90=360

2x=180

x=90

therefore the required angles of the rhombus are 90,90,90,90 and we know that all the sides of the rhombus are equal...hence it is a square..