Step-by-step.
30255.5=a90.75
Step 1: Cross-multiply.
30255.5=a90.75
(3025)*(90.75)=a*(5.5)
274518.75=5.5a
Step 2: Flip the equation.
5.5a=274518.75
Step 3: Divide both sides by 5.5.
5.5a5.5=274518.755.5
a=49912.5
The triangles are NOT similar.
If they were the ratios of the sides would be the same.
3 / 4 = .75
5 / 6 = .8333333333
6 / 8 = .75
1800/3 = 600
Every pound covers 600 square feet
8400/600 = 14
<span>14/4 = 3.5 (round up) so it would become 4.
</span>
You would need 4 bags.
I hope this helps!
Multiplying it would be 90x2 + 60x + 70x then simplify would be 90x2+130x