A square board 20 cm side has a corner triangle removed (right triangle, legs 5 cm each). What percent of the board remains?
96.88 %
Area of the square board = \(20 \times 20 = 400\) cm2.
Area of the removed right triangle = \(\frac{1}{2} \times 5 \times 5 = 12.5\) cm2.
Remaining area = \(400 - 12.5 = 387.5\) cm2.
Percentage remaining = \(\frac{387.5}{400} \times 100 = 96.875\% \approx 96.88\%\).
Hence, 96.88 % of the board remains.
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Important Questions from 2-D Mensuration
- The length of a rectangular plot is $(x^2 + xy + y^2)$ m and its breadth is $(x^2 - 5xy - y^2)$ m.
Find its perimeter, when $x = 1$ and $y = -1$. - The ratio between the perimeter and breadth of a rectangle is 3: 1. If the area of the rectangle is $98 \text{ cm}^2$, find the perimeter (in cm) of the rectangle.
The shorter side of a rectangle is 15 cm less than the longer side. The numerical value of its area is equal to 5 times the numerical value of its perimeter. What is the length (in cm) of its longer side?
- In a circle of radius 10.5 cm, if the angle of a sector is $\frac{2\pi}{3}$, then the perimeter of the sector is (in cm):
(Take $\pi = \frac{22}{7}$) - Find the circumference (in m) of the largest circle that can be inscribed in a rectangle whose dimensions are given as 114 m and 63 m.
Take $\pi = \frac{22}{7}$
