A 20-sided number cube is made up of equilateral triangles. Write and solve an equation to determine the value of x on the number cube shown.

The answer is below

Step-by-step explanation:

Triangle is a polygon with three sides and three angles. Types of triangles are equilateral, scalene, isosceles and right angled triangle. An equilateral triangle is a triangle in which all its sides are equal to each other, thereby each of its three angles measure 60°.

From the image of the 20 sided number cube, we can see that the length of each side of the equilateral triangle measures 13 mm. Therefore to find x, we use the formula:

x + 3.8 = 13

x = 13 - 3.8

x = 9.2 mm