A picture can help.
The median to the long side divides the isosceles triangle into two right triangles with hypotenuse 10 and short leg 6. Thus the long leg (median of interest) is found by the Pythagorean theorem to be
... √(10² -6²) = √64 = 8
Then the midpoint of the short side is found to be 6 + (6/2) = 9 units to the side and 8/2 = 4 units above the opposite vertex. Hence the square of the length of that median is 9² + 4² = 97.
The sum of squares of interest is
... 8² + 2×97 = 258
14.50 times 0.20 = 2.9
He would give a $2.90 as a tip of 20% from a bill of $14.50
Do 5.4 plus 5.8 then do 3.4w minus 1.8w and whatever you get for each is your key to the expression. So if you were to solve the answers like A you would do 7(1.6+w) and see what you would get. Obviously A isn't the answer. Sorry, this is hard to explain. But the answer is C
Vcone=1/3(hpir^2)
Vsphere=(4/3)pir^3
evaluate
vcone=1/3(1pi1^2)=pi/3
vsphere=4/3pi1^3=4pi/3
pi/3 times what=4pi/3
times both sides by 3
pi times what=4pi
divide both sides by pi
1 times what=4
what=4
4 cones