Rhombus ABCD has diagonals AC = 6 and BD = 8 that intersect at point E. Find the perimeter of rhombus ABCD.

Answer 1

The diagonals of a rhombus intersect each other at right angles.
So look at your diagram, each of the 4 triangles is a right-angled triangle
with short sides 3 and 4. Do yo recognize the 3-4-5 triangle??
then the sides of the rhombus are 5 units each
and the perimeter is 20 units