How many isosceles triangles with whole-number length sides have a perimeter of \(30\) units?
Let's count them: 8-8-14, 9-9-12, 10-10-10 11-11-8, 12-12-6, 13-13-4, 14-14-2
In total there are \(\color{brown}\boxed{7}\)
you forgot 10 10 10 (eqiuilateral triangles are isosceles triangles)
Isn't an equilateral triangle also considered isoceles?
If you agree with me that it is, then you can add 10-10-10 to the list.
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"An equilateral triangle is a triangle whose sides are all equal. It is a specific kind of isosceles"
I personally disagree, but I fixed it.
Thanks, Guest!
See if this helps:
https://www.mathsisfun.com/geometry/triangle-inequality-theorem.html
+2668 
