Answer:
x = 9
Step-by-step explanation:
84 + (7x + 5) + (180 - (17x-1)) = 180
84 + 7x + 5 + (181 - 17x) = 180
270 + (-10x) = 180
90 = 10x
x = 9
The <em>total</em> area of all six faces of the tunnel is 
square centimeters.
<h2>Procedure - Surface area of a tunnel for a toy train</h2>
The surface area of the solid (
) used to represent the tunnel for a toy train is the sum of its six faces (two <em>semicircular</em> sections, inner <em>semicircular</em> arc section, outer <em>semicircular</em> arc section, two rectangles).
<h3>Determination of the surface area of the tunnel based on information of the diagram</h3>
We calculate the surface area as following:
![A = 2\cdot \frac{\pi}{2} \cdot [(10\,cm)^{2}-(8\,cm)^{2}] + \pi\cdot (8\,cm)\cdot (30\,cm) + \pi\cdot (10\,cm)\cdot (30\,cm) + 2\cdot (2\,cm)\cdot (30\,cm)](https://tex.z-dn.net/?f=A%20%3D%202%5Ccdot%20%5Cfrac%7B%5Cpi%7D%7B2%7D%20%5Ccdot%20%5B%2810%5C%2Ccm%29%5E%7B2%7D-%288%5C%2Ccm%29%5E%7B2%7D%5D%20%2B%20%5Cpi%5Ccdot%20%288%5C%2Ccm%29%5Ccdot%20%2830%5C%2Ccm%29%20%2B%20%5Cpi%5Ccdot%20%2810%5C%2Ccm%29%5Ccdot%20%2830%5C%2Ccm%29%20%2B%202%5Ccdot%20%282%5C%2Ccm%29%5Ccdot%20%2830%5C%2Ccm%29)
The <em>total</em> area of all six faces of the tunnel is square centimeters. 
To learn more on surface areas, we kindly invite to check this verified question: brainly.com/question/2835293
Answer:
area = 693
Step-by-step explanation:
The area of a quadrilateral can be found using the formula; base * height
It is given that the height is 33, the base is 21;
Multiply the two
21 *33 = 693
Answer:
6.3 km.
Step-by-step explanation:
The question asks for kilometers, so all amounts have to be calculated in the same units -- kilometers.
Convert meters to kilometers.
600 m = .6 km
700 m = .7 km.
Add the amounts:
Fri.: .6 km
Sat. 3 km
Sun.: 2.7 km.
--------------------------------
6.3 km.
