In a right angled triangle where angle A is a right angle the Hypotenuse BC square equals AB square plus AC square
5 square plus 12 square equals 169 cm square square root 169 = 13
Therefore, BC= 13
To find the surface area of the prism
you have to find the area of the equal triangles and the area of the other three rectangular faces
area of the triangle is 5 X 12 = 60 divided by 2 = 30
the other triangle is equal
Now you go to the three rectangles
they have same height 20 which is the the same length for all
Now the width of the rectangles are the same length of the sides of the right angled triangle which are 5, 12 and 13
Therefore the area of the rectangle is length X width
Knowing the length is 20 X 5 = 100
20X12 = 240
20X13= 260
Add the area of the same triangles 30 each = 60
Now add and find the total
the base of a given triangular prism is a right angled triangle with AB=5cm,AC=12cm and the height of the prism =20cm. Angle A=90 degrees so calculate the surface area of the prism
1 answer
1 answer