Section 67
Exercises 67
A rectangular plate is 85 mm long and 42 mm wide. Find its area in square centimetres.
$$\left[35.7 \mathrm{~cm}^2\right]$$
A rectangular field has an area of 1.2 hectares and a length of 150 m . Find (a) its width and (b) the length of a diagonal ( 1 hectare $=10000 \mathrm{~m}^2$ ).[(a) 80 m(b) 170 m$]$
Determine the area of each of the angle iron sections shown in Fig. 18.11.[(a) $29 \mathrm{~cm}^2$(b) $650 \mathrm{~mm}^2$ I
A rectangular garden measures 40 m by 15 m . A 1 m flower border is made round the two shorter sides and one long side. A circular swimming pool of diameter 8 m is constructed in the middle of the garden. Find, correct to the nearest square metre, the area remaining.[ $482 \mathrm{~m}^2$ ]
The area of a trapezium is $13.5 \mathrm{~cm}^2$ and the perpendicular distance between its parallel sides is 3 cm . If the length of one of the parallel sides is 5.6 cm , find the length of the other parallel side.[ 3.4 cm ]
Find the angles $p, q, r, s$ and $t$ in Fig. 18.12(a) to (c).
$$\left[\begin{array}{r}p=105^{\circ}, q=35^{\circ}, r=142^{\circ} \\s=95^{\circ}, t=146^{\circ}\end{array}\right]$$
Name the types of quadrilateral shown in Fig. 18.13(i) to (iv), and determine (a) the area, and (b) the perimeter of each.$\left[\begin{array}{l}\text { (i) rhombus (a) } 14 \mathrm{~cm}^2 \text { (b) } 16 \mathrm{~cm} \\ \text { (ii) parallelogram (a) } 180 \mathrm{~cm}^2 \text { (b) } 80 \mathrm{~mm} \\ \text { (iii) rectangle (a) } 3600 \mathrm{~mm}^2 \text { (b) } 300 \mathrm{~mm} \\ \text { (iv) trapezium (a) } 190 \mathrm{~cm}^2 \text { (b) } 62.91 \mathrm{~cm}\end{array}\right]$
Calculate the area of the steel plate shown in Fig. 18.14
$$\left[6750 \mathrm{~mm}^2\right]$$