Answer: 6.93 years
Step-by-step explanation:
Given
Rate of interest is 
Future value is given by 
For the investment to double itself, i.e. 

It takes around 6.93 years to double the investment.
Answer:
x = 129°
Step-by-step explanation:
∠ ABD and ∠ DBC are a linear pair and sum to 180° , then
y + ∠ DBC = 180°
107° + ∠ DBC = 180° ( subtract 107° from both sides )
∠ DBC = 73°
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles , then
x = ∠ DBC + z = 73° + 56° = 129°
Answer:
72°
Step-by-step explanation:
From the question,
Area of the circle = πr²
A = πr²................. Equation 1
Where r = radius of the circle.
⇒ r = √(A/π)............. Equation 2
Given: A = 346.5 cm², π = 3.14
r = √(346.5/3.14)
r = √(110.35)
r = 10.5 cm.
Therefore,
circumference of the circle = 2πr = 2×3.14×10.5
circumference = 65.94 m
If the length of the arc(s) is 1/5 of its circumference.
Therefore, length of arc (s) = 13.188
⇒ length of arc/circumference = 13.188/65.94 = 1/5
s/2πr = θ/360
Where θ = angle substends at the center of the circle
1/5 = θ/360
θ = 360/5
θ = 72°