Hypotenuse = square root of (9602 + 4902)
= sqrt(1161700) = 1077.8 approx.
There is not enough information. Angle A can be anything between 0 and 180 degrees. If you are talking about a triangle ABC, in which angle C is the right angle then a is the opposite side and b is the adjacent side. tan A = opposite / adjacent tan A = 490 / 960 = 0.51041666666666666666666666666667 and A = invtan(0.51041666666666666666666666666667) [also called tan-1] so A = 27.04 degrees
30% of 960= 30% * 960= 0.3 * 960= 288
20% of 960 = 20% * 960 = 0.2 * 960 = 192
20% off of 960 = 80% left of 960 = 960*80/100 = 768
960 + 4% = 960*1.04 = 998.4