Question

the length of a hall is 20m and width 16m. the sum of the areas of the floor and the flat roof is equal to the areas of the four walls. find the height of the hall

Answer 1

area of four walls = 2(l+b).h

area of roof and floor = lb + lb = 2 lb

a/c to question ,

2(l+b).h = 2lb

(l+b)h = lb

(20+16).h = 20×16

36h = 320

h = 320/36 =80/9 = 8.89m

Hope it helps

Answer 2

Answer:

The height of hall is about 8.889 m.

Step-by-step explanation:

It is given that the length of a hall is 20m and width 16m.

The area of floor and roof is

$A_1=2(l\times b)=2\times (20\times 16)=640$

The area of 4 walls is

$A_2=2(l+b)h$

Where l is length, b is breadth and h is height.

$A_2=2(20+16)h$

$A_2=72h$

It is given that the area of floor and roof is equal to the area of 4 walls.

$A_1=A_2$

$640=72h$

$\frac{640}{72}=h$

$8.8888889=h$

$8.889\approx h$

Therefore the height of hall is about 8.889 m.