10)
You have cards going from 1 to 10, the only prime numbers between 1 and 10 are 2, 3, 5, 7
So from the 10 cards only 4 are primes, to get the probability you just need to divide them, probability = 4/10 = 40%
11)
This is a quarter of a circle then just calculate the circle area and divide by 4.
A = π.r² = π.14^2 = 196π
Dividing by 4
A = 49π