A right circular cylinder has a height of 12 cm and a total surface area of 110pi cm^2. What is the radius of its base?
Answer and explanation
Correct answer: B. r = -6 + sqrt(91) cm
- Step 1: The total surface area of a closed right circular cylinder is .
- Step 2: Substitute and : .
- Step 3: Divide by : .
- Step 4: Solve using the quadratic formula: .
- Step 5: Since radius must be positive and , .
Answer
r = -6 + sqrt(91) cm.
Why not the others: 'r = 5 cm' would require height (); 'r = 4 cm' yields ; 'r = 2.5 cm' yields .
Practise more Geometry, Trigonometry, and Quantitative Problem Solving.
Free questions with an explanation for every one, and full timed Kuwait University Aptitude Tests (KUAT) mock tests.
More Geometry, Trigonometry, and Quantitative Problem Solving questions
- What is the exact value of sin(75 degrees)?
- Find all solutions for theta in the interval [0, 2pi) that satisfy: 2 cos^2(theta) - cos(theta) - 1 = 0.
- In triangle ABC, side a = 7 cm, side b = 5 cm, and the included angle C = 60 degrees. Find the exact length of side c using the Law of Cosin…
- Find the center and radius of the circle defined by the equation: x^2 + y^2 - 6x + 8y - 11 = 0.
- What is the equation of the line passing through point (4, -2) that is perpendicular to the line 3x + 2y = 8?
- Find the area of a regular hexagon with a side length of 8 cm.