Question

the perimeter of parallelogram ABCD is 30 cm. AD 3 cm more then twice AB. find the length of AB. a) 3 cm b) 4 cm c) 9 cm d) 11 cm

Answer 1

its 4 centimeters :

4x2=8+3=11 so AD is 11 and AB is 4
since its perimeter you need it from each side and parallelograms have congruent opposite sides so 11+11+4+4=30 ;)

Answer 2

Option B.
`AB=4\ cm`

Explanation:

we know that

In a parallelogram opposite sides are congruent and parallel

so

`AB=CD`

`BC=AD`

the perimeter of parallelogram is equal to

`P=2(AB+AD)`

we have

`P=30\ cm`

so

`30=2(AB+AD)` ----->
`15=(AB+AD)` ----> equation A

`AD=2AB+3` -----> equation B

Substitute equation B in equation A and solve for AB

`15=(AB+2AB+3)`

`15-3=3AB`

`3AB=12`

`AB=4\ cm`