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

Answer:

Option B. $AB=4\ cm$

Step-by-step 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

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

$15-3=3AB$

$3AB=12$

$AB=4\ cm$