Question

An advertisement board is in the form of an isosceles triangle with its sides equal to 12m,10m and 10m. The cost of painting it at rupees 2.25 per m square is rupees 112.

Answer 1

Answer:

the total cost is Rs. 1050.

Step-by-step explanation:

Step-by-step explanation: AS given in the question and shown in the attached figure, ΔABC is an advertisement board, which is isosceles with AB = AC.

Also, AB = AC = 13 m  and perimeter is given by

P = AB+ BC+ CA=13+BC+13

36=26+BC

BC=10

Let us draw AD perpendicular to BC, so D will be the mid-point of BC, since ΔABC is isosceles.

Therefore, BD = CD = 5 m

So, from right-angled triangle ABD, we have, after using Pythagoras theorem -

AB^2 =AD^2+ BD^2

Hence, area of ΔABC is given by

A=*1/2*AD*BC=1/2*12*10=60m^2

Now, cost of painting 1 m² = Rs. 17.50

∴ Cost of painting 60 m² = Rs. (17.50 × 60) = Rs. 1050.

Thus, the total cost is Rs. 1050.