1. the area of the triangle minus the area of the small, inner rectangle. what did you not understand there ?
the standard formula (hi, internet !) for the area of a triangle is baseline×height/2.
the standard formula (hi, first grade !) for the area of a rectangle is length×width.
that's it.
1.a.
the volume of an object regularity shaped like a silo is always ground area times height.
for this object we only need to imagine to stand the object up sideways on the triangle side.
and don't forget - an area is always a square unit (like cm²,m², ft², ...). and a volume is always a cubic unit (like cm³, m³, ft³, ...).
so then, the triangle area is the ground area. and the original long side line of the object is is height.
as we said in 1. above, the area of a triangle is baseline×height (of the triangle, not of the overall object) divided by 2.
so, we have here 6×4/2 = 6×2 = 12 m²
and now the ground area × object height = 12×8=96 m³
b.
the standard formula for the volume of a ball (hi, internet !) is pi×r³.
so, we have here pi×9³. can you calculate that with your calculator ? that is pi×729 = 2290.221 cm³
2a.
the height of the cone is (as the drawing already suggests) determined via the right-angled triangle of the radius (half of the diameter) of the ground circle, the height of the cone and the length of the sideline on the outside mantle of the cone. this sideline is the Hypotenuse (the baseline of the triangle opposite of the 90 degree angle).
so, we use Pythagoras
c² = a² + b² (c being the Hypotenuse, a and b being the sides).
11² = 8² + h²
121 = 64 + h²
h² = 57
h = 7.55 cm
2b.
the standard formula for the volume of a cone (hi, internet !) is
pi×r²×h/3
pi×8²×7.55/3 = pi×64×7.55/3 = 506 cm³
Step-by-step explanation:
all of that you could easily search on the internet and since it yourself way faster than putting things in here and waiting for responses.
as there is really nothing to explain but just to use the standard formulas with the given numbers.
