Problem with two review problems

[maverick99]

First of all, thanks for anyone who helps me with this

1. Find the perimeter of an Isoceles triangle that has base angles of 36 degrees and an area of 580cm sq.
The given answer is 126.4cm.

2. A designer plan the top of a rectangular workbench to be four times as long as it is wide, and then determines that if the width is 2.5 ft greater and the length is 4.7ft less, it wouldbe a square. What are its dimensions?

 

[dextercioby]

First of all, thanks for anyone who helps me with this

1. Find the perimeter of an Isoceles triangle that has base angles of 36 degrees and an area of 580cm sq.
The given answer is 126.4cm.

2. A designer plan the top of a rectangular workbench to be four times as long as it is wide, and then determines that if the width is 2.5 ft greater and the length is 4.7ft less, it wouldbe a square. What are its dimensions?

1.& 2.What have you done so far?The problems are not difficult,and therefore it's better that u did them yourself,maybe with some help from us.Post your work.

Daniel.

 

[maverick99]

1.& 2.What have you done so far?The problems are not difficult,and therefore it's better that u did them yourself,maybe with some help from us.Post your work.

Daniel.

I just need help starting both of them, that's all.

 

[futb0l]

Well - what's the formula in getting the area of the triangle??
You should start off with that.

 

[maverick99]

Well - what's the formula in getting the area of the triangle??
You should start off with that.

well i know that its 1/2(b)(h) but i don't know what it means by 2 base angles of 36 degrees. Since it's isocoles, doesn't it have a right angle, therefore 36+36+90=162 which it should add up to 180

 

[dextercioby]

well i know that its 1/2(b)(h) but i don't know what it means by 2 base angles of 36 degrees. Since it's isocoles, doesn't it have a right angle, therefore 36+36+90=162 which it should add up to 180

I doubt the original problem was formulated with a triangle on a saddle (negative total curvature),but in a plane,so those angles should add up to 180°.
U'll find more useful this formula:
S_{triangle}=\frac{1}{2}l_{1}l_{2} \sin \alpha
,where \alpha is the angle between those 2 sides l_1 and l_2.

Daniel.

 

[futb0l]

isosceles doesn't mean right angle it's just
36+36+ 108 = 180