Answer:
1.
a. 20 m²: barn door is 5m x 4m
b. 468 m²:surface area of barn
i. left and right barn walls: 2(15 x 7) = 210
ii. back wall: 7 x 8 = 56
iii. front wall: (7 x 8) - 20* = 36
*20 for the barn door
iv. front of roof: (4 x 4) / 2 = 8 x 2* = 16
*I split the triangle into 2 smaller triangles
v. sides of roof: 2(5 x 15) = 150
2.
a. 15 m²: silo door is 3m x 5m
b. 244.18 m²: surface area of silo
i. SA(silo)=2πrh+2πr²
ii. SA(silo) = 2π(2.5)(14) + 2π(2.5)²
iii. SA(silo) = 259.18
iv. SA(silo - door) = 259.18 - 15
v. SA(silo - door) = 244.18
3.
a. 712.18 m²: total surface area painted red
i. add both surface areas: 468 + 244.18 = 712.18 m²
hope this helps :)
