Explain how you can use mental. math to perform the following addition

Mathematics

1 answer:

yKpoI14uk [10]4 years ago

5 0

You can use mental math to perform the following addition by knowing that certain numbers equal a certain number. for instance, you know that 9+2 is equal to 11. you don't need a calculator to solve that. then you know that 1+8 is equal to 9.since you are adding 11 you know that the answer is 19. you can use that to answer to following equation.

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Y W P 8 cm E R WERP is a square. Find.

BlackZzzverrR [31]

1) All interior angles of a square are right angles, so angle WER measures 90°

2) All squares are parallelograms, and diagonals of a parallelogram bisect each other, meaning PA=AE=8 cm. Thus, PE=16 cm

3) All squares are rectangles, and diagonals of a rectangle are congruent, meaning WR=16 cm. Then, using the fact that the diagonals bisect each other, we get that WA=8 cm

4) If we consider right triangle WPR, we know it is isoceles because all sides of a square are congruent. So, the length of WP is:

$\frac{16}{ \sqrt{2} } = 8 \sqrt{2}$