Rain is falling vertically with a speed of 25m/s. A cyclist is going at a speed of 10m/s in the north to south direction. What is the apparent speed of the rain and direction of the cyclist to hold his umbrella, so that cyclist wont get wet? b)
Answers
Answer:
The length, area and the perimeter of the rectangle are 21cm, 420 cm² and 82 cm respectively.
Step-by-step explanation:
Let the rectangle be ABCD.
According to the question :
➟ Diagonal : BD = 29cm
➟ Breadth : CD = 20cm
All the angles in a rectangle are 90°.
So, ∆BDC is a right angled triangle with ∠BCD = 90°. Using pythagoras theorem :
➟ (P)² + (B)² = (H)²
➟ (BC)² + (20)² = (29)²
➟ BC² + 400 = 841
➟ BC² = 841 – 400
➟ BC² = 441
➟ BC = √441
➟ BC = 21cm
∴ The length of the rectangle BC is 21 cm.
Now, let's find the area of the rectangle :
➟ Area of rectangle = Length × breadth
➟ A = 21cm × 20cm
➟ Area = 420cm²
∴ The area of the rectangle is 420 cm².
Finally, finding the perimeter of the rectangle :
➟ Perimeter = 2 (l + b)
➟ P = 2 (21cm + 20cm)
➟ P = 2 (41cm)
➟ Perimeter = 82cm
∴ The perimeter of the rectangle is 82 cm.
Explanation: