Triangle abc is a right traingle if side ac=7 and side bc = 10 what is the measure of ab?

For a right triangle with legs legnth a and b and hypotnuse (longes side) legnth c

a²+b²=c²

depends which one is the hyppotonuse

if we assume that bc is the hypotnuse, then

7²+b²=10²

49+b²=100

minus 49

b²=51

sqrt both sides

the missing side is √51

if we assume that the hypotonuse is ab then

7²+10²=c²

49+100=c²

149=c²

sqrt both sides

√149=c

if bc is the hypotonuse, then ab is √51

if ab is the hypotonuse, then ab is √149