Sorry, I don't understand your question... But, if you're trying to find how triangles are congruent, congruent means Same Size and Same Shape.
The answer should be C. By combining like terms you can find the answer. 1.75a+2.75a = 4.5a
2.25b + 1.75b = 4b
2.25c + 1.25c = 3.5c
divide 9 by 10. (the numerator and denominator) = 9 / 10 = 0.9
add the 0.9 to the 3 so, 3 + 0.9 = 3.9
answer: 3.9
Because algebra means finding the unknown
it is usually used in real life
for example if if 1/2 of the legnth of a line is 8 then what is the legnth
so then 1/2 x=8 and that is algebraic
since it has x, or an unknown in it, it is an algebraic expression
I kind-of need more specifics here. You didn't give any dimensions, but okay. So if you notice, from the side, any cone just looks like a regular old triangle. And we can treat it like one when trying to find the slant height. Ever heard of the Pythagorean theorem? a squared plus b squared = c squared. so in this case, the hypotenuse, or c-side, will be your slant height. take the square of the distance from the circle-base's center to the apex. add that to the square of the radius of the base. Find the square root (using your calculator) of that sum, and there's your answer.