50 tens and 9 ones is less than 49 tens and 35 ones because 50 tens is 500 + 9 is 509, whereas 49 tens is 490 + 35.
The answer is 50 because the formula for the area of a triangle is base x hight x 1/2. So if we plug both the 10s into the formula you get 10x10 which = 100 then divide that by 2 and you get 50. Hope it helps :)
