На клетчатой бумаге с размером клетки \( 1 \times 1 \) изображена трапеция. Найдите её площадь.

5. A tree is broken at a height of 5 m from the ground and its top touches the ground at a distance of 12 m from the base of the tree. Find the original height of the tree.

12-variant 1. \( A(4 ; 3 ;-2), B(-3 ;-1 ; 4), C(2 ; 2 ; 1\} ; \) \( a=\overrightarrow{A B}, b=\overrightarrow{A C}, c=\overrightarrow{C B}, d=2 c-5 b, \quad l=C B, \alpha=4, \beta=3 \)

Find the area of the sector of a at the centre is \( 140^{\circ} \). (Take \( \pi= \) Solution Area A of a sector is given by; \( \begin{aligned} \text { A }=\frac{\theta}{360} \times \pi r^{2}\end{aligned} \) \( \begin{aligned} \therefore \text { Area } & =\frac{140}{360} \times \frac{22}{7} \times 3^{2} \\ & =11 \mathrm{~cm}^{2}\end{aligned} \)

4. Which of the following can be the sides of a right triangle? (i) \( 2.5 \mathrm{~cm}, 6.5 \mathrm{~cm}, 6 \mathrm{~cm} \). (iii) \( 2 \mathrm{~cm}, 2 \mathrm{~cm}, 5 \mathrm{~cm} \). (iii) \( 1.5 \mathrm{~cm}, 2 \mathrm{~cm}, 2.5 \mathrm{~cm} \).

\( A B C \) үшбұрышында \( B C \) биссектрисасы сызылған, \( A K=5 \mathrm{~cm} \) және \( K S=7 \mathrm{~cm} A B C \) үшбұрышының периметрі 48 cm AB және BC қабырғаларын табыңыз.