Respuesta :

Answer:

1. (12+24+20+28)÷4=21

2. 6× 9^2= 486 cm^2

3. a. Length^2

b. Length× breadth

c. (1/2)× base × perpendicular height

area= (1/2)× 12cm × 13cm= 78 cm^2

perimeter = 14+14+12= 40cm

Step-by-step explanation: