5% is just another way of writing 5/100
So we have 5/100 of 88.5 → 5100×88.5
This is the same as 5×88.5/100=5×0.885
But 5 is 1/2×10
So we can write 5×0.885 as 1/2×10×0.885
=1/2×8.85=4.425
hope it helps!
Answer:
<abd+<dbc=<Abc
50+40=90
triangle abc is a right angled triangle being one angle 90 degree
Well, you can find out if your estimate is reasonable by finding out the actual answer to see if you guessed close.
