(5 x 8 - 12)(36 : 9 x 4)
= (40 - 12)(4 x 4)
= 28 x 16
= 448
Answer:
3,432 m²
Step-by-step explanation:
The amount of aluminum in square meters needed to make the mailboxes = 1863(surface area of each mailbox)
Surface area of each mail box = ½(surface area of cylinder) + (Surface area of rectangular prism/box - area of the surface of the box that joins the half-cylinder)
✔️Surface area of ½-cylinder = ½[2πr(h + r)]
r = ½(0.4) = 0.2 m
h = 0.6 m
π = 3.14
Surface area of ½-cylinder = ½[2*3.14*0.2(0.6 + 0.2]
= 0.628(0.8)
Surface area of ½-cylinder = 0.5024 m²
✔️Surface area of the rectangular box/prism = 2(LW + LH + WH)
L = 0.6 m
W = 0.4 m
H = 0.55 m
Surface area = 2(0.6*0.4 + 0.6*0.55 + 0.4*0.55)
Surface area of rectangular box = 1.58 m²
✔️Area of the surface joining the half cylinder and the box = L*W = 0.6*0.4 = 0.24 m²
✅Surface area of 1 mailbox = (0.5024) + (1.58 - 0.24)
= 0.5024 + 1.34
= 1.8424
Amount of aluminum needed to make 1863 mailboxes = 1863 × 1.8424 = 3,432.3912
= 3,432 m²
Answer:
C. 434π
Step-by-step explanation:
Given:
Radius (r) = 7 in.
Height (h) = 24 in.
Required:
Surface area of the cylinder
Solution:
S.A = 2πrh + 2πr²
Plug in the values
S.A = 2*π*7*24 + 2*π*7²
S.A = 336π + 98π
S.A = 434π
Answer is 4 so C for you. I just did this with my brother! Hope this helped.
