Answer:
By comparing the ratios of sides in similar triangles ΔABC and ΔADB,we can say that 
Step-by-step explanation:
Given that ∠ABC=∠ADC, AD=p and DC=q.
Let us take compare Δ ABC and Δ ADB in the attached file , ∠A is common in both triangles
and given ∠ABC=∠ADB=90°
Hence using AA postulate, ΔABC ≈ ΔADB.
Now we will equate respective side ratios in both triangles.

Since we don't know BD , BC let us take first equality and plugin the variables given in respective sides.

Cross multiply

Hence proved.
All are relations except for relation 3
Answer:
My hero acadamia. I didnt spell that right. Its on hulu.
Step-by-step explanation:
Average of 2 numbers is 40
so total = 2 x 40 = 80
300 - 80 = 220
average of remaining 10 numbers = 220/10 = 22
answer
B) 22