Answer: The answer is the straight line 'ad'.
Step-by-step explanation: Given are two planes named 'aed' and 'adcb'. We are to find the intersection of these two planes.
We are familiar with some well-known facts from geometry. For example -
(i) Two parallel lines never intersect each other.
(ii) The intersection of two non parallel lines is a point.
(iii) The intersection of two planes, if intersect, is a straight line, etc.
In planes 'aed' and 'adcb', the points 'a' and 'd' lie on both the planes. So, the line drawn through these two points, i.e., line 'ad' will also lie on the two planes. And, since intersection of two planes is a line, therefore, line 'ad' is the intersection of planes 'aed' and 'adcb'.
Thus, the intersection of planes 'aed' and 'adcb' is line 'ad'.