Answer: 11, 23, 166
Explanation:
Hiya! From the drawings, I'm assuming all of the triangles are right-angled triangles. If they aren't though, tell me and I'll tell you how to solve them.
Anyways, assuming they are right angled-triangles, you can use Pythagoras' Theorem (aka a² + b² = c²)
c is the hypotenuse or the side opposite the right angle.
a and b are just the other two sides (doesn't really matter which is which)
Question 7:
c² = a² + b²
12² = a² + 5²
144 = a² + 25
144 - 25 = a²
119 = a²
a = 10.908712114635714411502154487373
(To the nearest whole number: 11)
Question 8:
c² = a² + b²
24² = 7² + b²
576 = 49 + b²
576 - 49 = b²
527 = b²
b = 22.956480566497992703585747092065
(To the nearest whole number: 23)
Question 9:
c² = a² + b²
c² = 90² + 140²
c² = 8,100 + 19,600
c² = 27,700
c = 166.43316977093238068928214785346
(To the nearest whole number: 166)
Hoped this helped! Tell me if there's something you don't understand. :)