Is there more to questions. you can solve it with little info
7² + 3² = c²
49 + 9 = c²
58 = c²
c = √58
To find area you simply multiply 5 and 4 which is 20
ANSWER
The explicit rule is

EXPLANATION
The given sequence is :
54,63,72,81,...
The first term of this sequence is

The common difference is

The explicit rule is given by:


We expand to get:


None of them is correct .