Lines AB and CD being perpendicular means the angles where they meet are all 90°. The diagonal line divides two of those 90° angles into two parts (each). The whole (90°) is the sum of the parts into which the angle has been divided.
The sum of angles 3 and 4 is 90°. Once you understand this relationship, you can write an equation based on the relationship. The equation can be solved in the usual way.
The sensitive period for language is from 7 months in utero up to 5.5 to 6 years of age. There are several aspects of language from spoken language, to written language and reading. ... The sensitive period for learning to speak is from is from 7 months to 2.5-3 years of age.
