Multiple joins display student course name - oracle

Question

I have the following setup, which is working perfectly. I am difficulty figuring out the syntax how to display the course name in the output. In my test CASE all the rows should have the value Geometry.
In addition, how could I use rank or rank_dense to limit the output to display only 1 row with the highest average?
CREATE TABLE students(student_id, first_name, last_name) AS
SELECT 1, 'Faith', 'Aaron' FROM dual UNION ALL
SELECT 2, 'Lisa', 'Saladino' FROM dual UNION ALL
SELECT 3, 'Leslee', 'Altman' FROM dual UNION ALL
SELECT 4, 'Patty', 'Kern' FROM dual UNION ALL
SELECT 5, 'Betty', 'Bowers' FROM dual;
CREATE TABLE courses(course_id, course_name) AS
SELECT 1, 'Geometry' FROM dual UNION ALL
SELECT 2, 'Trigonometry' FROM dual UNION ALL
SELECT 3, 'Calculus' FROM DUAL;
CREATE TABLE grades(student_id,
course_id, grade) AS
SELECT 1, 1, 75 FROM dual UNION ALL
SELECT 1, 1, 81 FROM dual UNION ALL
SELECT 1, 1, 76 FROM dual UNION ALL
SELECT 2, 1, 100 FROM dual UNION ALL
SELECT 2, 1, 95 FROM dual UNION ALL
SELECT 2, 1, 96 FROM dual UNION ALL
SELECT 3, 1, 80 FROM dual UNION ALL
SELECT 3, 1, 85 FROM dual UNION ALL
SELECT 3, 1, 86 FROM dual UNION ALL
SELECT 4, 1, 88 FROM dual UNION ALL
SELECT 4, 1, 85 FROM dual UNION ALL
SELECT 4, 1, 91 FROM dual UNION ALL
SELECT 5, 1, 98 FROM dual UNION ALL
SELECT 5, 1, 74 FROM dual UNION ALL
SELECT 5, 1, 81 FROM dual;
/* average grade of each student */
select s.student_id
, s.first_name
, s.last_name
, round(avg(g.grade), 1) as student_avg
from students s
join grades g
on s.student_id = g.student_id
group by s.student_id, s.first_name, s.last_name
ORDER BY avg(g.grade) DESC;

Answer 1

Something like this?
SQL> with temp as
2 (select s.student_id
3 , s.first_name
4 , s.last_name
5 , c.course_name
6 , round(avg(g.grade), 1) as student_avg
7 , rank() over (order by avg(g.grade) desc) rnk
8 from students s join grades g on s.student_id = g.student_id
9 join courses c on c.course_id = g.course_id
10 group by s.student_id, s.first_name, s.last_name, c.course_name
11 )
12 select student_id, first_name, last_name, course_name, student_avg
13 from temp
14 where rnk <= 3
15 order by rnk;
STUDENT_ID FIRST_ LAST_NAM COURSE_NAME STUDENT_AVG
---------- ------ -------- ------------ -----------
2 Lisa Saladino Geometry 97
4 Patty Kern Geometry 88
5 Betty Bowers Geometry 84.3
SQL>