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. 
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Answer:

Step-by-step explanation:
see the attached figure with letters to better understand the problem
Let
a ----> the height of rectangle in mm
b ---> the base of rectangle in mm
step 1
Find the base of rectangle
----> by segment addition postulate
substitute

step 2
Find the height of rectangle
---> by segment addition postulate
substitute the given values

Find the length sides CG
Applying the Pythagorean Theorem

substitute the given values



simplify

therefore

step 3
Find the area of rectangle

we have


substitute

Answer:
b) median: there are 7 numbers listed; 20 is the middle number among them
range: subtract lowest from highest number 25-2=23
mean: add all the numbers together =129
mode: place numbers in order (smallest to greatest), then see which number appears the most 2, 18, 18, 20, 22, 24, 25=18
Step-by-step explanation:
5 sig figs is the correct answer