Can someone please explain how to solve these please!!!

16) 54cm^2

17) 16cm^2

Step-by-step explanation:

16) b² + h² = H²

12² + h = 15²

144 + h = 225

h = 225 - 144

h = √81

h = 9

A = 1/2 x b x h

A = 1/2 x 12 x 9

A = 54cm²

17) same method as no 16

h + 9 = 25

h = 25 - 9

h = √16

h = 4

A=1/2 x b x h

A = 1/2 x 3 x 4

A = 16cm²

you would have to sell 24 bracelets.

step-by-step explanation:

84/3.5 = 24