135 because 10+5= 15. 15(9)=135. 6-5=1. so 135/1=135
Here we are given the three sides of the triangle.
So we have Heron's formula to find its area.
Heron's formula is given by :

where A, B and C are sides of triangle and S is semi perimeter which is given by,

plugging values of A, B and C to find S

S=13.5
Now plugging values of A, B , C and S in Heron's formula

A=26.14 mm²
Answer: Area of triangle is 26.14 mm².
V = (1/3)pi*r^2*h that's the formula to used to get the volume of the cone
3.14/5.71=0.18330414466 years
hope this hepls