Prove that sin10cos20 = cos80sin70 (where the numbers are in degrees).
sin10 = cos(90-10) = cos80 cos20 = sin(90-20) = sin70 hence sin10cos20 = cos80sin70 based on complimentary angle theory.
A ring is used to make a circle. The area of a circle is 314 cm sq. Now if the ring is converted to a square, what will be the area of the square hence formed.
Area of circle = 3.14 X r X r = 314. Hence radius of circle is 10 cm. Therefore length of the ring = circumference of the circle = 2 X 3.14 X r = 62.8 cm Now, this ring is converted to a square. Hence each side of the square measures 62.8/4 cm Hence each side of the square = 15.7 cm Area of square = side X side = 15.7^2 cm sq = 246.49 cm sq.
A boy went to the market and bought 4 bananas worth $x each. He also brought a chocolate for $2. The total amount he paid for both the bananas and the chocolate was $8. What is the cost per piece of the banana?
The equation formed is of the form: 4x + 2 = 10. Solving the above equation, 4x = 8 and hence x = 2. Therefore the price of the bananas is $2 each.