Question : Plants bring positively and calmness in environment. Ruhi bought a glass pyramid planter with square base for her office. She grew cacti in it and used it as a centre piece in her office.
i) What is the area of each isosceles triangular glass frame ? [1 Mark]
ii) A student pugged in the value a = 15cm, b = 14cm, c = 13cm and s=42 cm in the formula
A=√[s(s-a)(s-b)(s-c)]
What does A stand for in the formula? a, b, c and s have their usual meaning in the formula. [1 Marks]
iii) Find the total length of the brass frame used to connect all sides walls and base. [2 Marks]
Doubt by Purvi
Solution :
(i) Here
Base (b) = 10 cm
Each Equal side (a) = 13 cm
Base (b) = 10 cm
Each Equal side (a) = 13 cm
Area of each isosceles triangle
=(b/4)[√(4a²-b²)]
=(10/4)[√(4×(13)²-(10)²)]
=2.5[√(676-100)]
=2.5√576
=2.5×24
=60 cm²
(ii) A stands for Area of the Triangle by Heron's Formula.
=(b/4)[√(4a²-b²)]
=(10/4)[√(4×(13)²-(10)²)]
=2.5[√(676-100)]
=2.5√576
=2.5×24
=60 cm²
(ii) A stands for Area of the Triangle by Heron's Formula.
(iii) Total length of the brass frame used
= 4×base (b) + 4×Equal Side (a)
= 4b+4a
=4(b+a)
= 4×base (b) + 4×Equal Side (a)
= 4b+4a
=4(b+a)
=4(10+13)
=4×23
=92 cm
=4×23
=92 cm