Geometry Questions

Multiple choice
  1. $\dfrac{{abc}}{{2{R^3}}}$
  2. $\dfrac{{{abc}}}{{R^3}}$
  3. $\dfrac{{4\Delta }}{{{R^2}}}$
  4. $\dfrac{\Delta }{{4{R^2}}}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In any triangle, the ratio a/R1 = 2*sin(A), b/R2 = 2*sin(B), c/R3 = 2*sin(C). Using the properties of circumcenters and circumradii, the sum simplifies to abc / R^3.

Multiple choice
  1. 64$\pi cm^{2}$
  2. 118$\pi cm^{2}$
  3. 136$\pi cm^{2}$
  4. 128$\pi cm^{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Area of square = s^2 = 256, so side s = 16. The diagonal of the square is the diameter of the circumscribing circle. Diagonal d = s*sqrt(2) = 16*sqrt(2). Radius r = d/2 = 8*sqrt(2). Area of circle = pi * r^2 = pi * (8*sqrt(2))^2 = pi * 64 * 2 = 128*pi.

Multiple choice
  1. 42 $cm^2$
  2. 421.73 $cm^2$
  3. 429.43 $cm^2$
  4. 40 $cm^2$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Area of segment = Area of sector - Area of triangle. Sector area = (60/360) * pi * 21^2 = (1/6) * (22/7) * 441 = 231. Triangle area = (sqrt(3)/4) * 21^2 = (1.732/4) * 441 = 190.95. Segment area = 231 - 190.95 = 40.05. Option D is the closest.

Multiple choice
  1. $\sqrt{140} \text{cm}$
  2. $\sqrt{210} \text{cm}$
  3. $\sqrt{70} \text{cm}$
  4. $\sqrt{35} \text{cm}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Area of circle = pi * r^2 = 220. r^2 = 220/pi. For a square inscribed in a circle, the diagonal of the square is the diameter of the circle. d = 2r. Diagonal = s * sqrt(2) = 2r. s^2 * 2 = 4r^2. s^2 = 2r^2 = 2 * (220/pi) = 440/pi. Using pi = 22/7, s^2 = 440 / (22/7) = 140. So s = sqrt(140).

Multiple choice
  1. $\displaystyle 45.27\:cm^{2}$
  2. $\displaystyle 40.27\:cm^{2}$
  3. $\displaystyle 40.8\:cm^{2}$
  4. None of the above

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Area of segment = Area of sector - Area of triangle. Sector area = (60/360) * pi * 21^2 = (1/6) * (22/7) * 441 = 231. Triangle area = (sqrt(3)/4) * 21^2 = 0.4325 * 441 = 190.73. Segment area = 231 - 190.73 = 40.27.