area of first figure=444
area of second figure=57
area of third figure=132
Explanation
The first figure
has 9 faces, 2 triangular and 7 rectangular.
bottom face-rectangle
length=16
breadth=5
area=l*b=16*5=80(1)
two similar rectangular faces
length=16
breadth=4
area=l*b=16*4=64
area of two faces=2*64=128(2)
two similar rectangular faces
length=5
breadth=4
area=5*4=20
area of two faces=2*20=40(3)
two top slant faces-rectangular
length=10
breadth=5
area=10*5=50
area of two faces=2*50=100(4)
two triangular top faces
base=16
height=6
area=1/2 bh=1/2 *16*6=48
area of two faces=2*48=96(5)
total area of the structure=(1)+(2)+(3)+(4)+(5)=80+128+40+100+96=444
The second figure
It has two triangles
triangle 1
length=7
breadth=3
area1=l*b=21
triangle 2
length=9
breadth=4
area2=l*b=9*4=36
total area=area1+area2=21+36=57
The third figure
It has a rectangle and triangle
rectangle
length=20
breadth=6
area1=l*b=20*6=120
triangle
base=20-(8+6)=20-14=6
height=10-6=4
area2=1/2 bh=1/2*6*4=12
total area=area1+area2=120+12=132
