Answer:
a)
b)
Step-by-step explanation:
Q11 a) ABCD is a parallelogram, then units.
Consider triangles AED and BEF. In these triangles
by reflexive property;
are corresponding angles formed when parallel lines BC and AD are intersected by transversal AE. By corresponding angles theorem, they are congruent.
By AA similarity theorem, . Similar triangles have proportional corresponding parts, so
ABCD is a parallelogram, then units, so
Q11b) ABCD is a parallelogram, then units. By segment addition postulate,
Consider triangles EBF and ECD. In these triangles,
by reflexive property
are corresponding angles formed when parallel lines AB and CD are intersected by transversal EC. By corresponding angles theorem, they are congruent.
So, by AA similarity theorem. Similar triangles have proportional corresponding parts, so
From the first equality,
From the second equality: