The gable shown in the diagram is the triangular portion of the wall between the edges of the sloping roof. Triangle ABC is an isosceles triangle. Side CB is 12 feet 4 inches long. Sides AB and AC are each 0.75 of this length. What is the perimeter of triangle ABC?

I don't quite understand this question I know the formula for perimeter is A+B+C and I took 12.4 and divided it by .75 to get the side lengths for AB and AC then followed the perimeter formula but It doesn't come out as any of the following answers :

18 ft 6 in.
21 ft 7 in.
31 ft 4 in.
30 ft 10 in.

Question

The gable shown in the diagram is the triangular portion of the wall between the edges of the sloping roof. Triangle ABC is an isosceles triangle. Side CB is 12 feet 4 inches long. Sides AB and AC are each 0.75 of this length. What is the perimeter of triangle ABC?

I don't quite understand this question I know the formula for perimeter is A+B+C and I took 12.4 and divided it by .75 to get the side lengths for AB and AC then followed the perimeter formula but It doesn't come out as any of the following answers :

18 ft 6 in.
21 ft 7 in.
31 ft 4 in.
30 ft 10 in.

anonymous · Answer

ans is 30ft 10 in

u want to know how???

anonymous · Answer

Yes please!

anonymous · Answer

side CB is 12ft 4 in = total 148 in
0.75 of BC = 0.75 * 148 in = 111 in = 9 ft 3 in
so AB = AC = 9 ft 3 in

so AB + BC + AC = 9 ft 3 in  +  12 ft 4 in  +  9 ft 3 in  =  30 ft 10 in

amistre64 · Answer

$\color{red}{\small\text{12.4}}$ isnt the decimal equivalent of 12' 4inches :)

anonymous · Answer

yes amistre is correct, 12.4 ft  is not same as 12ft 4 in

anonymous · Answer

Thank you! I understand it now!

anonymous · Answer

:)