Question

7. Use short-cut method to find the squares of the following numbers which end in 5:
(i) 252
(ii) 552
(iii) 852
(iv) 952
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Answer 1

Step-by-step explanation:

(252)²

= (200+ 50 + 2)²

= 200² + 50² + 2² + (2×200×50) + (2×50×2) + (2×2×200)

= 40000 + 2500 + 4 + 20000 + 200 + 800

= 63504

(552)²

= (500 + 50 + 2)²

= 500² + 50² + 2² + (2×500×50) + (2×50×2) + (2×2×500)

= 250000 + 2500 + 4 + 50000 + 200 + 2000

= 304704

(852)²

= (800 + 50 + 2)²

= 800² + 50² + 2² + (2×800×50) + (2×50×2) + (2×2×800)

= 640000 + 2500 + 4 + 80000 + 200 + 3200

= 725904

(952)²

= (900 + 50 + 2)²

= 900² + 50² + 2² + (2×900×50) + (2×50×2) + (2×2×900)

= 810000 + 2500 + 4 + 90000 + 200 + 3600

= 906304

Now let me tell you the formula I used.

This is the formula.

(a+b+c)² = a² + b² + c² + 2ab + 2bc + 2ca

Hope you liked the answer. Please mark as brainliest because it took me a lot of time.