https://image.prntscr.com/image/2CfTpJgDRH639tqNuHxpQg.png part one
https://image.prntscr.com/image/ekkO73wWQtK2PrSsFuRRuA.png part two
https://image.prntscr.com/image/LxFBRHQPQ5GglmKxv50O-g.png
First one
2. Corresponding Angles
3. Triangle JKL similar to Triangle JMN AA similarity
4. Corresponding Parts of Similar Triangles form equal ratios
5. Segment Addition Postulate
6. Substitution
9. Subtracion Property of Equality
Second one
They are similar by AA congruency
The areas are in ratio PQ^2 / AB^2 = (4k)^2 / 4^2 = 16k^2 / 16 = k^2