1. obtuse angle is shown, 45° is missing. 2. obtuse angle is shown, 29° is missing. 3. acute angle is shown, 65° is missing. 4. acute angle is shown, 40° is missing. 5. acute angle is shown, 42° is missing. 6. acute angle is shown, 100° is missing. 7 an obtuse angle and a acute angle are shown, 54° (for number 1) and 126° (for number 2) are missing. 8. an obtuse and a acute angle are shown, 45° (for 1) and 135° (for 2) are missing.
All numbers that only have one and itself as factors are prime. Therefore, to tell if a number is prime simply find it's factors. If it has more than two factors than it is not a prime number.
