Answer: No 18—- x = 11.1
No 19—- x = 8.1
No 20—- Perimeter = 62.9
Step-by-step explanation: Looking at the figure in question 18, x is the radius of the circle. Also the line beside it that runs from the center down to the other edge of the arc is also the radius. That other radius is divided into 6.5 and 4.6. Adding them both together gives us
6.5 + 4.6 = 11.1
Remember that this line is also the radius, hence x equals 11.1
From figure in No 19, the radius is 16, and upon careful observation you would see that the other radius is part of an upside down right angled triangle. One of the other two sides is 13.9, and the third side can be calculated as
16^2 = 13.9^2 + y^2
16^2 - 13.9^2 = y^2
256 - 193.21 = y^2
62.79 = y^2
Add the square root sign to both sides of the equation
7.9 = y
Note that the line made up of x and y runs from the center to the circumference of the circle (that is, radius). So line x equals 16 minus y
x = 16 -y
x = 16 - 7.9
x = 8.1
And then, from the figure in No 20 the two lengths and the two widths are not equal. However we can determine the ratio of similarity of the two widths and apply this in finding the missing length. In other words, W1/W2 = L1/L2
15.5/16.8 = 14.7/x
By cross multiplication we now have
x = (14.7 x16.8)/15.5
x = 246.96/15.5
x = 15.93
Therefore the perimeter of the figure is given as;
Perimeter = 14.7 + 15.5 + 15.9 + 16.8
Perimeter = 62.9
