Question

Please help me by answering 1 and 2 example. Please fast

Answer 1

Radius of first circle=8cm

Area =πr^2=π64=64π

Radius of second circle =6cm

Area =36π

Sum of areas of first circle=area of third circle=64π+36π=100π=10×10×π=π×r×r

Radius of third circle=10cm

Diameter of wheel is 80cm

radius =40 cm

One revolution means length covered which is equal to circumference

Circumference=2πr=2π40cm=251.2cm

$1cm = 10 ^{ - 5} km$

circumference=251.2×10^-5km

Time 10min=1/6hours

speed=66kmph

distance =speed×time=66×1/6=11km

No of revolution=distance/circumference=11/251.2×10^-5=4378.9

=4378 complete revolution or say approximately 4379 revolution