For 18a, use the similar triangles concept. The trick is to just follow the vertices stated and don't need to go and trace and draw it out whatsoever. so question says ABC is similar to ADE, just follow the order.

For the first part, i believe one u use my trick, it will be easy. For the second part, remember your angle properties, since DE is parallel to AB, i can use the corresponding angles property. OR u can find DEB which is 180 - 33.7 since DE and AB are parallel to each other then take 180 - DEB to get CED. Then the last step should be easy for u, the total angle in a triangle is 180 degrees.