Question

bhai aur beheno plss help in que 4

Answer 1

Answer:

Given that

Diameter of a circle (d) = 1 1/4 cm = 5/4 cm

So, radius of each circle (r) = 5/8 cm

Area of the aluminium strip = 8 3/4 × 1 1/4 cm²

= 35/4 × 5/4 cm²

= 175/16 cm²

= 10.9375 cm²

Area of each circle

= π × r²

= π × (5/8)² cm²

= 25π/64 cm²

The diameter of the circle = breadth of the strip

So, number of circles

$\frac{length \: \: of \: the \: strip}{ diameter \: of \: the \: circle}$

= (8 3/4) / (1 1/4)

= (35/4) / (5/4)

= 7 [Ans.]

So, total area of circle

= 7 × 25π/64 cm²

= 275/32 cm² (put π = 22/7)

= 8.590 cm²

So, area wasted

= area of the strip - area of the total circles

= 10.9375 cm²- 8.590 cm²

= 2.34375 cm²

Hope it will help you ✌️

Answer 2

Sᴏʟᴜᴛɪᴏɴ :-

Given That :-

→ Length of Rectangular Aluminium Strip = 8(3/4) = (35/4) cm.

→ Diameter of Circles To be cut = 1(1/4) = (5/4) cm.

Now, we can cut circles upto Length of Rectangular Aluminium Strip.

So,

→ Total Circles cut = (35/4) ÷ (5/4) = (35/4) * (4/5) = 7 Circles (Ans.)

______________________

Now,

→ Length of Rectangular Aluminium Strip = (35/4)cm.

→ Breadth of Rectangular Aluminium Strip = (5/4) cm.

So,

→ Area of Rectangular Aluminium Strip = Length * Breadth = (35/4) * (5/4) = (175/16)cm².

And,

→ Diameter of Each Circle = (5/4) cm.

→ Radius of Each circle = (5/4) * (1/2) = (5/8) cm.

So,

→ Area of one Circle = π * (Radius)² = (22/7) * (5/8)² = (22/7) * (25/64) cm².

Therefore,

→ Area of 7 such Circles = 7 * (22/7) * (25/64) = (550/64) cm².

______________________

Hence,

→ The wastage of Aluminium Strip = Area of Rectangular Aluminium Strip - Area of 7 circles

→ The wastage of Aluminium Strip = (175/16) - (550/64) = (175*4 - 550)/64 = (150/64) = (75/32) = 2(11/32)cm². (Ans.)