Question

If two circles intersect each other at the point Cand D. Two straight lines through points D and C interasect one circle at the points A and B and the other circle at the points E and F respectively. If angle DAB = 75°, then find the value of angle DEF​

Answer 1

two circles intersect at each other at C & D

AB is their common tangent.

Also, given 

to prove that

∠ACB+∠ADB=180o

∠CBA=∠CDB−−−−−−(1)

∠CAB=∠CDA−−−−−−−(2)

∠CDB+∠CDA=∠CBA+∠CAB→eq(1)

∠CBA+∠CAB+∠ACB=180o

∠CBA+∠CAB=180o−∠ACB−−−−−eq(2)

from (1) & (2)

∠CDB+∠CDA=180o−∠ACB

∠CDB+∠CDA=∠ADB

=180o−∠ACB−∠ADB

∠ADB=180o−∠ACB

∴∠ADB+∠ACB=180o

Answer 2

Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide with each other