Answer:
d) I assume x is the missing angle
the sum of the angles of a triangle = 180°.
2.5x°+20°+40°+20°=180°
2.5x+80=180
2.5x=180-80
x=40°
e)square of area 64cm²
the area of a square =c²
side = V64 =8cm
f) rectangle with area 35cm²
sides: x and (x+2)
A =x(x+2)=x²+2x
x²+2x=35
x²+2x-35=0
solve by factoring :
I write2x as a difference: x²+7x-5x-35=0
we factor
x(x+7)-5(x+7)=0
(x+7)(x-5)=0
x+7=0 x=-7
x-5=0 x = 5
a length is never negative: x= 5
rectangle width = 5cm
rectangle length = 7cm
Explanation: