a. 28 * 63
28 (60) + 28 (3) or 20 (60) +20 (3) + 8 (60) + 8 (3)
1680 + 84=1764 1200 / 60 +480 +24=1764
b. 17(59)
17 (50) + 17 (9) or 10 (50) + 10 (9) + 7 (50) +7 (3)
850 + 153=1003 500 + 90 + 63 =1003
c.458 (15)
458 (10) +458 (5) or 10 (400) + 10 (50) + 10 (8) + 5 (400) +5 (50) + 5 (8)
4580 +2290 = 6870 400 + 500 + 80 + 2000 + 250 + 40 = 6870
My work is kinda confusing but hope it helped
Hi there!

tan (angle) = Opposite side / Adjacent side, so:
Tan (A) = opposite side / adjacent side
= 24 / 10
Simplify:
= 12 / 5
Since this is a triangle all the angles within the triangle add up to 180 degrees so....
82+(9x+2)+(7x)=180
82+2+16x=180
16x+84=180
16x=96
X=6
If we plug in X to angle(9x+2) and angle (7x) we will get 56 and 42. We can get angle 2 by subtracting 180-42 which is 138
FINAL ANSWER: 138 degrees