Question

From a semicircular region OABCD, a (ABD in which AB = 3 cm and BD = 4 cm is removed. Find the perimeter​

Answer 1

Answer:

Step-by-step explanation:

Please find the solved answer along with the diagram attached.  

We have : AB = 3 CM; BD = 4 CM

We know that, angle in a semi-circle is a right angle

So, ∠ABD = 90°  

So, ∆ABD is a right ∆

Now, AD² = BD²+AB² =AD² = 4² + 3² = 16+9 = 25

=AD = 5 cm So, diameter, AD = 5 cm

Now, circumference of semi-circle OABCD = Π x Radius + diameter = 3.14x2.5+5 = 12.85 cm

Now, when the triangle ABD is removed then the figure becomes (attached file)

So, circumference of the remaining figure = 7.85+AB+BD = 7.85+3+4 = 14.85 cm