Question

45. Figure 13.105, shows the cross-section of railway tunnel. The radius OA of the circular
part is 2 m. If AOB = 90°, calculate:
(i) the height of the tunnel
(ii) the perimeter of the cross-section
(iii) the area of the cross-section.​

Answer 1

Answer:

2, 7.14 , 3.14

Step-by-step explanation:

as there is no figure in question

i m assuming that the question was asked about AOB cross section. then

height of tunnel = radius = 2m

perimeter = {(2×π×r)÷4 } + 2r = 3.14 + 4 = 7.14m

area of cross section AOB = area of circle÷4

= πr^2 ÷ 4 = (3.14×4)÷4

= 3.14 m^2