Question

Find the value of the unknown in each of the following figures.

please help me :(​

Answer 1

Answer:

43°

Step-by-step explanation:

107°+121+3a=360°

288+3a=360

3a=132

a=43

Answer 2

First, you need to know the sum of internal angles. Sum of internal angles of n sided polygon is given as (n-2)×180°.(Try for yourself in case of triangle which has 3 sides)

Figure-a:

Total sides, n = 5

Sum of internal angles = (5-2) × 180 = 3×180 = 540°

Adding the given angles, 107 + a + a + 121 + a = 540

⇒ 3a + 228 = 540

⇒ 3a = 540 - 228 = 312

⇒ a = 312/3

⇒ a = 104

Similarly, in Figure-b:

Total sides, n = 6

Sum of internal angles = (6-2) × 180 = 4×180 = 720°

Adding the given angles, 128 + 114 + 104 + 4b + 3b + 122 = 720

⇒ 7b + 468 = 720

⇒ 7b = 720 - 468 = 252

⇒ b = 252/7

⇒ b = 36