The size of the triangle does not matter!
What two facts do you know about the interior angles of an isosceles triangle
the sum total of the angles = 180 degrees
the angles opposite the equal sides are also equal
They will be the same
= square of the ratio of their sides
divide side triangle 1 by side triangle 2
square the result
multiply that result by the area of triangle 1
1/2 base X height
Height might be outside the triangle!
3 4 5
5 12 13
s s s√2 (Great for squares, when asked the diagonal of a square)!!
s/√2, s/√2, s also great for squares
s 2s s√3 for 30 60 90 triangles - favorite test question. Hyp is 2s
why? area = base²
but base² + base² = diagonal ² ; 2base² =diagonal ²;
therefore area = base²= 1/2diagonal ²
what is the circumference of a circle
what is the surface area of a rectangular solid
what is the surface area of a cylinder
The side = circumference * height (2¶r * h) plus
the top and bottom = 2(¶r²)
Don't forget the top and bottom!
(x-h)² + (y-k)² = r² where h and k are the center points and r is the radius
(Number of sides - 2) * 180
Triange - 180
square = (4-2) * 180 = 360
pentagor - (5-2) * 180 = 540
what is the volume of a cylinder
height X circumference (or height X ¶r²)