Find the sum of the interior a angles of a regular decagon (10-sided figure).

1440°

rule to find total sum any interior angles: (n - 2) * 180

where n is the number of sides

here deca mean 10

so 10 sides

(10-2) * 180

1440°

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.