Question

Please someone help me answer my question need help

Answer 1

Look at the picture.

The triangle ADC and the triangle CDB are similar.

Therefore corresponding sides are all in the same proportion:

`(y)/(4)=(12)/(y)\ \ \ \ |cross\ multiply\\\\y^2=48\to y=√(48)\\\\y=√(16\cdot3)\\\\y=√(16)\cdot\sqrt3\\\\y=4\sqrt3`

Answer: 4√3