Aesi
In the above examples, the lower part of 安 is the radical in both which means "onna", correct? How can I learn to look at an unfamiliar kanji and know which part of it is the radical?
Radicals are tricky business, but memorizing them will go a long way to helping you learn. The "dominate radical" is usually what characterizes the kanji (its typically the "ben" on the far left) and, if the kanji retains its Chinese heritage, you can some times guess the Chinese
onyomi reading. Also, many electronic dictionaries search kanji by radical so it helps to know them. The only really tricky ones are 肉which is actually written as the 月radical but some dictionaries still retain the 肉stroke count (6 strokes as opposed to 4).