Question
From the top of a lighthouse, the angle of depression to
the top and bottom of a tower is 30° and 45°, respectively. If the lighthouse is 210 metres high, then find the height of the tower.Solution
Let AB and CD be the heights of the light house and the tower, respectively So, AB = 210 metres, ∠ ADE = 30° and ∠ ACB = 45° Now, in right angled triangle ABC tan45° = AB/BC So, AB/BC = 1 Or, AB = BC So, BC = 210 metres And, BC = DE = 210 metres So, in right angled triangle AED, tan30° = AE/DE Or, AE = 210 × (1/√3) Or, AE = 70√3 Also, CD = BE So, height of tower CD = AB – AE = 210 – 70√3 = 70√3(√3 – 1) metres
Which of the following is used to eliminate redundancy and anomalies in a database?
Which command is used to remove all records from a table without deleting the table structure?
The result of a Cartesian product of two relations R and S will have:
Which OOP principle allows a single interface to represent different underlying forms or data types?
Which of the following is true about a view in SQL?
A primary key in a table:
Which SQL keyword is used to sort the result set?
The concept of "data hiding" is primarily achieved through which OOP principle?
Which of the following is a valid constraint in SQL?
Which of the following statements about abstract classes is true?
Relevant for Exams:
