Ni : Zn: Cu = 7:2:9 =7x : 2x : 9x
7x+2x+9x = 3.8
18x=3.8
x=3.8/18=1.9/9≈0.21
Ni: 7x=7*0.21=1.47 ≈1.5 kg
Zn: 2x=2*0.21=0.42≈0.4 kg
Cu: 9x=9*0.21=1.89 ≈1.9 kg
Check 1.5+0.4+1.9 =3.8 True
25.13cm^2 or 8pi. The radius of a circle is 2 x pi x r^2. R is the radius. 2 x pi x 2^2cm -> 2 x pi x 4cm -> 8cm x pi -> 25.13cm^2. Leaving the answer in terms of pi would be 8pi.
Answer = B = 376 degrees - 3x
180=11+2x
-11 -11
169/2=2x\2
x=84.5
