1) On sides AB and BC of square ABCD equilateral triangles ABE and BCF are constructed as shown. Prove that points D, E, and F are collinear.
![2399_equilateral triangles.png](https://secure.tutorsglobe.com/CMSImages/2399_equilateral%20triangles.png)
2) In right triangle ABC with the right angle at C, CH is an altitude and AC = AM. Prove that ∠1 = ∠2.
![1022_equilateral triangles1.png](https://secure.tutorsglobe.com/CMSImages/1022_equilateral%20triangles1.png)
3) In isosceles triangle ABC [AB = AC] P is an arbitrary point on base BC and E is on the extension of side AC so that CE = CP. Prove that ∠AFE = 3∠AEF.
4) The lengths of the sides of a triangle are 2x + 6, 4x, and 8x - 3. For what values of x is this triangle isosceles? Justify your answer.
![1867_equilateral triangles2.png](https://secure.tutorsglobe.com/CMSImages/1867_equilateral%20triangles2.png)
Attachment:- geometry.pdf