Answer:
230.3cm^2
Step-by-step explanation:
surface area: sum of all faces
base: 12 x 2.5 = 30cm^2
back: 84 cm ^2
cross section x 2 = 7 x 2.5 = 17.5
use Pythagoras theorem to find the width of slope: 7^2 + 2.5^2 = 49 + 6.25 = 55.25. square root of 55.25 = 7.4
so, area of slope : 7.4 x 12 = 88.8cm^2
sum of all areas: 114 + 106.3 = 230.3
[ Answer ]

[ Explanation ]
- Simplify: -0.8b + 4.1c - (-3.2b) - 0.1c
-----------------------------------
-0.8b + 4.1c + 3.2b - 0.1c
-0.8b + 3.2b + 4.1c - 0.1c
- Add Similar Elements: -0.8b + 3.2b = 2.4b
2.4b + 4.1c - 0.1c
- Add Similar Elements: 4.1c - 0.1c = 4c
2.4b + 4c
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OK so here it goes:
1a. 10³
1b. 10²
1c. 10(tiny 6)
1d. 10³
1e. 10(tiny6)
1f. 10(tiny 5)
2a. 400
2b. 640,000
2c. 5,400
2d. 5,301,000
2e. is it multipcation or addition
2f. 607,200
2g. 0.948
2h. 0.0094
3a) 0.02, 0.2, 2, 20, 200, 2000
3b) 3,400,000 ; 34,000; 340, 3.4, 0.034
3c) 85,700; 8,570; 857, 85.7, 8.57, 0.857
3d) 444, 4440, 44,400; 440,000; 4,400,000; 44,000,000
3e) 0.95, 9.5, 950, 95,000; 950,000; 9,500,000
Hope this helps.
Step-by-step explanation:

4 tens = 40 and 5 tens = 50 … therefore the number has to be between 40 and 50
So: 40 < x <50 … this says that x is greater than 40 and less than 50
So the possible numbers would be: 41,42,43,44,45,46,47,48,49
Now the number must have 9 ones … which mean the only number would be 49