KANGAROO MATHS

Areas of TrianglesIt can be useful to think of a triangle as half of a square or parallelogram.The area of a triangle is (height width) 2. The area of the three triangles in the diagram above is the same.The area of each triangle is 4.5cm2

Areas of CirclesIn order to calculate the area of a circle you need to know itsradiusordiameter.

(diameter = radius 2) (radius = diameter 2)circle area = R2.This means: = Pi is a constant that equals 3.142.R = is the radius of the circle.R2(radius squared) means radius radius.Therefore acircle with a radius of 5 cm, has an area of:3.142 5 5 = 78.55cm2.Acircle with a diameter of 3 mhas an area:First we work out the radius (3 m 2 = 1.5m)Then apply the formula: R23.142 1.5 1.5 = 7.0695.The area of a circle with a diameter of 3m is 7.0695m2

1. The sum of the interior angles in a regular polgyon is equal to 180(n-2), where n is the number of sides of the polygon.#Sides in a Regular PolygonnSum of Interior Angles180(n-2)Measure of Each Interior Angle[180(n-2)]/nSum of Exterior Angles360o

318060360o

436090360o

5540108360o

6720120360o

7900128.57360o

81080135360o

91260140360o

101440144360o

Dear aspirants below you can find the important and basicformulas of CDSE HCF and LCM questions. These formula will help you to solve most of the questions appear inCDSE maths paper. Mathematics paper of CDSE generally consist questions from algebra, arithmetic, mensuration, geometry, trigonometry, trigonometry, logarithm and statistics. Below you can findCDSE questions from HCF and LCM with important formula.

CDSE Maths Formula on HCF and LCM1. Factors and Multiples: If number a divided another number b exactly, we say that a is a factor of b. In this case, b is called a multiple of a.2. Highest Common Factor (H.C.F.)or Greatest Common Measure (G.C.M.) or Greatest Common Divisor (G.C.D.): The H.C.F. of two or more than two numbers is the greatest number that divided each of them exactly. There are two methods of finding the H.C.F. of a given set of numbers:1. Factorization Method: Express the each one of the given numbers as the product of prime factors. The product of least powers of common prime factors gives H.C.F.1. Division Method: Suppose we have to find the H.C.F. of two given numbers, divide the larger by the smaller one. Now, divide the divisor by the remainder. Repeat the process of dividing the preceding number by the remainder last obtained till zero is obtained as remainder. The last divisor is required H.C.F.1. Finding the H.C.F. of more than two numbers: Suppose we have to find the H.C.F. of three numbers, then, H.C.F. of [(H.C.F. of any two) and (the third number)] gives the H.C.F. of three given number.1. Similarly, the H.C.F. of more than three numbers may be obtained. Least Common Multiple (L.C.M.): The least number which is exactly divisible by each one of the given numbers is called their L.C.M. There are two methods of finding the L.C.M. of a given set of numbers:. Factorization Method: Resolve each one of the given numbers into a product of prime factors. Then, L.C.M. is the product of highest powers of all the factors.. Division Method (short-cut): Arrange the given numbers in a rwo in any order. Divide by a number which divided exactly at least two of the given numbers and carry forward the numbers which are not divisible. Repeat the above process till no two of the numbers are divisible by the same number except 1. The product of the divisors and the undivided numbers is the required L.C.M. of the given numbers. Product of two numbers = Product of their H.C.F. and L.C.M. Co-primes: Two numbers are said to be co-primes if their H.C.F. is 1. H.C.F. and L.C.M. of Fractions:. H.C.F. = H.C.F. of Numerators / L.C.M. of Denominators. L.C.M. =L.C.M. of Numerators / H.C.F. of Denominators H.C.F. and L.C.M. of Decimal Fractions:. In a given numbers, make the same number of decimal places by annexing zeros in some numbers, if necessary. Considering these numbers without decimal point, find H.C.F. or L.C.M. as the case may be. Now, in the result, mark off as many decimal places as are there in each of the given numbers. Comparison of Fractions:. Find the L.C.M. of the denominators of the given fractions. Convert each of the fractions into an equivalent fraction with L.C.M as the denominator, by multiplying both the numerator and denominator by the same number. The resultant fraction with the greatest numerator is the greatest.- See more at: http://www.ssbcrack.com/2013/09/cdse-maths-formula-of-hcf-and-lcm.html#sthash.YO6K6RVY.dpuf

Example: If a triangle with a base of 10ft has the same area as a circle with radius 3ft, then what is the height of the triangle? A triangle, a circle? Areas? Huh? Is there a formula? How do they relate? They don't, but what you'll need to figure out is that you are merely dealing with the area formula for a triangle and a circle, both of which are easy formulas. A circle with radius of 3ft has an area of pi*r2, and ifr=3, then the area of the circle is 9pi. So 9pi is equal to the area of a triangle, and we know that the area formula for a triangle is base times height, divided by 2 (and we know that the base is 10). So we set up the following equation, and follow through with the calculations:9pi=(10 * height) / 2

18pi=10 * height

18pi/10=height

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