Question

Building A is 285.5 m tall and building B is 300 m tall. By how many metres is building B taller than building A? .
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Answer 1

Refer to the attachment please

Answer 2

A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with mirrors at each end set parallel to each other at a 45° angle.