What is the perimeter of the triangle

perimeter=sum of all side=2x-5+(-7x+8)+3x=2x-5-7x+8+3x=3-2x

Step-by-step explanation:

Area of the circle = 1400π

ie. πr^2 = 1400π . ie r^2 =1400. So r=10√14

Area A = πr^2.Differentiate w.r.t.t

dA/dt = 2πr. dr/dt

900 = 2×π×10√14 .dr/dt

So. dr/dt = 900/2×π×10√14 = 45/π√14 m/sec.

Hope this answer helps you :)

Have a great day

Mark brainliest