There are two corresponding angles shown and one included angle meaning the angle is in-between the two sides, allowing this to be characterized by SAS similarity.
Multiplying and dividing with conjugate of 2+i in the given expression, we get(3+ 4i)(2-i)/(2+i)(2-i)=(6-3i+8i-4i^2)/(4-i^2)=(10+5i)/(4+1)=(10+5i)/5=2+i=a+bi<span>Thus a=2</span>
