If log 7 - log 2 + log 16 - 2 log 3 - log $\dfrac{7}{45}$ = 1 + log k, find the value of k.

Evaluate :

$\dfrac{\text{log } 8 \times \text{log } 9}{\text{log }27}$

In the given figure, D is mid-point of AB, DE//BC and DF//AC. Prove that : DE = BF.

State, true or false, for each of the following statements.

(i) If three angles of two triangles are equal, the triangles are congruent.

(ii) If two sides of a right triangle, containing right angle, are equal to corresponding sides of another right triangle, the triangle are congruent.

(iii) If two triangles are congruent, then the corresponding angles are equal.

(iv) If two angles and a side of one triangle are equal to two angles and a side of another triangle, the triangles are congruent.